explanation blue bibcodes open ADS page with paths to full text
Author name code: korendyke
ADS astronomy entries on 2022-09-14
author:"Korendyke, Clarence M."
---------------------------------------------------------
Title: The CCOR-1 Compact Coronagraph: Description and Ground
Calibration Results
Authors: Thernisien, Arnaud; Carter, Michael; Chua, Damien; Korendyke,
Clarence; Socker, Dennis; Babich, Timothy; Baugh, Rebecca; Bonafede,
Jo; Boyer, Darrell; Brown, Samuel; Corsi, Keith; Cremerius, Luke;
Crippa, Cameron; Davis, Joseph; Gardner, Larry; Clifford, Greg;
Hohl, Bruce; Hagood, Robert; Koehler, Matthew; Hunt, Tonia; Kuroda,
Natsuha; Lanagan, Andrew; Lynch, Brian; Ogindo, Moses; Noya, Mario;
Pellak, Kenneth; Podgurski, Robert; Bordlemay-Padilla, Yadira; Rich,
Nathan; Silver, Daniel; Simmons, Jeff; Smith, Linda; Spitzak, John;
Tanner, Steven; Uhl, Andrew; Verzosa, Julius; Wiggins, Grayson;
Wilson, Courtni; Zurcher, Dallas
2021AGUFMSH43B..08T Altcode:
The Compact Coronagraph (CCOR) on the Geostationary Operational
Environmental Satellite, GOES-U series, will be one of the cornerstone
instruments for space weather forecasting for the National Oceanic and
Atmospheric Administration (NOAA), after the scheduled GOES-U spacecraft
launch in 2024. The CCOR instrument will monitor the solar corona
and detect coronal mass ejections (CMEs) that are directed towards
Earth for at least 5 years of GOES-U operations. This presentation
describes the CCOR instrument, its planned operations in the GOES-U
geosynchronous orbit, and the instrument performance based on ground
test measurements and calibration. The Office of Projects Planning
and Analysis (OPPA) at NOAA funded the Naval Research Laboratory to
develop, build and test the CCOR instrument.
---------------------------------------------------------
Title: The Solar-C (EUVST) mission: the latest status
Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kawate, Tomoko; Suematsu,
Yoshinori; Hara, Hirohisa; Tsuzuki, Toshihiro; Katsukawa, Yukio; Kubo,
Masahito; Ishikawa, Ryoko; Watanabe, Tetsuya; Toriumi, Shin; Ichimoto,
Kiyoshi; Nagata, Shin'ichi; Hasegawa, Takahiro; Yokoyama, Takaaki;
Watanabe, Kyoko; Tsuno, Katsuhiko; Korendyke, Clarence M.; Warren,
Harry; De Pontieu, Bart; Boerner, Paul; Solanki, Sami K.; Teriaca,
Luca; Schuehle, Udo; Matthews, Sarah; Long, David; Thomas, William;
Hancock, Barry; Reid, Hamish; Fludra, Andrzej; Auchère, Frederic;
Andretta, Vincenzo; Naletto, Giampiero; Poletto, Luca; Harra, Louise
2020SPIE11444E..0NS Altcode:
Solar-C (EUVST) is the next Japanese solar physics mission to
be developed with significant contributions from US and European
countries. The mission carries an EUV imaging spectrometer with
slit-jaw imaging system called EUVST (EUV High-Throughput Spectroscopic
Telescope) as the mission payload, to take a fundamental step towards
answering how the plasma universe is created and evolves and how the
Sun influences the Earth and other planets in our solar system. In
April 2020, ISAS (Institute of Space and Astronautical Science) of JAXA
(Japan Aerospace Exploration Agency) has made the final down-selection
for this mission as the 4th in the series of competitively chosen
M-class mission to be launched with an Epsilon launch vehicle in mid
2020s. NASA (National Aeronautics and Space Administration) has selected
this mission concept for Phase A concept study in September 2019 and
is in the process leading to final selection. For European countries,
the team has (or is in the process of confirming) confirmed endorsement
for hardware contributions to the EUVST from the national agencies. A
recent update to the mission instrumentation is to add a UV spectral
irradiance monitor capability for EUVST calibration and scientific
purpose. This presentation provides the latest status of the mission
with an overall description of the mission concept emphasizing on key
roles of the mission in heliophysics research from mid 2020s.
---------------------------------------------------------
Title: A sensitivity analysis of the updated optical design for
EUVST on the Solar-C mission
Authors: Kawate, Tomoko; Tsuzuki, Toshihiro; Shimizu, Toshifumi;
Imada, Shinsuke; Katsukawa, Yukio; Hara, Hirohisa; Suematsu, Yoshinori;
Ichimoto, Kiyoshi; Hattori, Tomoya; Narasaki, Shota; Warren, Harry P.;
Teriaca, Luca; Korendyke, Clarence M.; Brown, Charles M.; Auchere,
Frederic
2020SPIE11444E..3JK Altcode:
The EUV high-throughput spectroscopic telescope (EUVST) onboard the
Solar-C mission has the high spatial (0.4”) resolution over a wide
wavelength range in the vacuum ultraviolet. To achieve high spatial
resolution under a design constraint given by the JAXA Epsilon launch
vehicle, we further update the optical design to secure margins
needed to realize 0.4” spatial resolution over a field of view of
100”×100”. To estimate the error budgets of spatial and spectral
resolutions due to installation and fabrication errors, we perform a
sensitivity analysis for the position and orientation of each optical
element and for the grating parameters by ray tracing with the Zemax
software. We obtain point spread functions (PSF) for rays from 9
fields and at 9 wavelengths on each detector by changing each parameter
slightly. A full width at half maximum (FWHM) of the PSF is derived at
each field and wavelength position as a function of the perturbation
of each optical parameter. Assuming a mount system of each optical
element and an error of each optical parameter, we estimate spatial
and spectral resolutions by taking installation and fabrication errors
into account. The results of the sensitivity analysis suggest that
budgets of the total of optical design and the assembly errors account
for 15% and 5.8% of our budgets of the spatial resolution in the long
wavelength and short wavelength bands, respectively. On the other hand,
the grating fabrication errors give a large degradation of spatial and
spectral resolutions, and investigations of compensators are needed
to relax the fabrication tolerance of the grating surface parameters.
---------------------------------------------------------
Title: The Solar Orbiter Heliospheric Imager (SoloHI)
Authors: Howard, R. A.; Vourlidas, A.; Colaninno, R. C.; Korendyke,
C. M.; Plunkett, S. P.; Carter, M. T.; Wang, D.; Rich, N.; Lynch,
S.; Thurn, A.; Socker, D. G.; Thernisien, A. F.; Chua, D.; Linton,
M. G.; Koss, S.; Tun-Beltran, S.; Dennison, H.; Stenborg, G.; McMullin,
D. R.; Hunt, T.; Baugh, R.; Clifford, G.; Keller, D.; Janesick, J. R.;
Tower, J.; Grygon, M.; Farkas, R.; Hagood, R.; Eisenhauer, K.; Uhl,
A.; Yerushalmi, S.; Smith, L.; Liewer, P. C.; Velli, M. C.; Linker,
J.; Bothmer, V.; Rochus, P.; Halain, J. -P.; Lamy, P. L.; Auchère,
F.; Harrison, R. A.; Rouillard, A.; Patsourakos, S.; St. Cyr, O. C.;
Gilbert, H.; Maldonado, H.; Mariano, C.; Cerullo, J.
2020A&A...642A..13H Altcode:
<BR /> Aims: We present the design and pre-launch performance of
the Solar Orbiter Heliospheric Imager (SoloHI) which is an instrument
prepared for inclusion in the ESA/NASA Solar Orbiter mission, currently
scheduled for launch in 2020. <BR /> Methods: The goal of this paper
is to provide details of the SoloHI instrument concept, design, and
pre-flight performance to give the potential user of the data a better
understanding of how the observations are collected and the sources
that contribute to the signal. <BR /> Results: The paper discusses
the science objectives, including the SoloHI-specific aspects, before
presenting the design concepts, which include the optics, mechanical,
thermal, electrical, and ground processing. Finally, a list of planned
data products is also presented. <BR /> Conclusions: The performance
measurements of the various instrument parameters meet or exceed the
requirements derived from the mission science objectives. SoloHI is
poised to take its place as a vital contributor to the science success
of the Solar Orbiter mission.
---------------------------------------------------------
Title: Imaging the Solar Corona From Within
Authors: Hess, P.; Howard, R.; Vourlidas, A.; Bothmer, V.; Colaninno,
R.; DeForest, C.; Gallagher, B.; Hall, J. R.; Higginson, A.; Korendyke,
C.; Kouloumvakos, A.; Lamy, P.; Liewer, P.; Linker, J.; Linton, M.;
Penteado, P.; Plunkett, S.; Poirer, N.; Raouafi, N.; Rich, N.; Rochus,
P.; Rouillard, A.; Socker, D.; Stenborg, G.; Thernisien, A.; Viall, N.
2020AAS...23514907H Altcode:
Parker Solar Probe (PSP), launched, in August 2018 is humanity's
first probe of a stellar atmosphere. It will make measurements of
the near-Sun plasma from 'within' the outer corona with gradually
reduced perihelia from its first perihelia of 35 Rs in 2018-19 to 9.8
Rs in 2025. Here we report the results from the imaging observations
of the electron and dust corona, whe PSP was 35-54 Rs from the solar
surface, taken by the Wide-field Imager for Solar Probe (WISPR). The
spacecraft was near-corotating with the solar corona throughout the
observing window, which is an unprecedented situation for any type of
coronal imaging. Our initial analysis uncovers a long-hypothesized
depletion of the primordial dust orbiting near the Sun, reveals the
plasma structure of small-scale ejections, and provides a strict test
for validating model predictions of the large-scale configuration of
the coronal plasma. Thus, WISPR imaging allows the study of near-Sun
dust dynamics as the mission progresses. The high-resolution images
of small transients, largely unresolved from 1 AU orbits, unravel
the sub-structures of small magnetic flux ropes and show that the
Sun continually releases helical magnetic fields in the background
wind. Finally, WISPR's observations of the coronal streamer evolution
confirm the large-scale topology of the solar corona but they also
reveal that, as recently predicted, streamers are composed of yet
smaller sub-streamers channeling continual density fluctuations at
all visible scales.
---------------------------------------------------------
Title: The Compact Heliospheric Imager (CHI): An R2O Instrument
Concept for an L5 Space Weather Mission
Authors: Chua, D. H.; Thernisien, A.; Korendyke, C.; Socker, D. G.;
Noya, M.
2019AGUFMSH43F3351C Altcode:
The payload complements specified for most L5 Lagrange point space
weather mission concepts include a white-light coronagraph as
the primary means to detect the eruption of coronal mass ejections
(CMEs) and to establish their initial trajectory into interplanetary
space. The design goal outer field of view for an L5 coronagraph is
typically about 25 R<SUB>Sun</SUB>. Once an Earth-directed CME leaves
the L5 coronagraph's outer field of view, it loses track of the event
and no information about its trajectory or speed is available to
operational heliospheric disturbance propagation codes. Forecasters
would be blind until the CME reaches the L1 Lagrange point along the
Sun-Earth line, where the in-situ measurements would provide only
30-45 minutes of actionable lead time prior to the CME impact at
Earth. Adding a heliospheric imager to the instrument suite of an L5
space weather mission will enhance its ability to continuously track
CMEs as they leave the L5 coronagraph field of view, improving CME
trajectory determination, CME arrival time estimation, and ultimately
the accuracy of geomagnetic storm forecasts. The Compact Heliospheric
Imager (CHI) is a dual-telescope instrument concept with 30° fields
of view that is an ideal candidate for this role on an L5 space weather
mission. CHI will image interplanetary space in white light (500-700 nm)
between 4.5°-64.5° elongation from L5. This combined field of view
encompasses the entire Sun-Earth line with Earth just inside the outer
field of view cut off. CHI's enclosed design allows it to be placed
close to other spacecraft components or instruments without those
components interfering with CHI's imaging performance. This provides a
great deal of flexibility in placement of CHI on a spacecraft since
its only requirement is to have an unobstructed field of regard
(FOR) in the Sun-facing hemisphere. CHI's compact design and low
power requirements make it an ideal instrument candidate for an L5
space weather mission. The CHI concept development is supported by
the ONR/NRL Bids and Proposals (B&P) Program.
---------------------------------------------------------
Title: Imaging the Solar Corona from Within: First Results from the
Parker Solar Probe Telescope
Authors: Howard, R. A.; Vourlidas, A.; Bothmer, V.; Colaninno, R. C.;
DeForest, C.; Gallagher, B.; Hall, J. R.; Hess, P.; Higginson, A. K.;
Korendyke, C.; Kouloumvakos, A.; Lamy, P.; Liewer, P. C.; Linker, J.;
Linton, M.; Penteado, P. F.; Plunkett, S. P.; Poirier, N.; Raouafi,
N.; Rich, N.; Rochus, P. L.; Rouillard, A. P.; Socker, D. G.; Stenborg,
G.; Thernisien, A.; Viall, N. M.
2019AGUFMSH11A..04H Altcode:
Parker Solar Probe (PSP) launched in August 2018 is humanity's
first probe of a stellar atmosphere. It will make measurements of
the near-Sun plasma from 'within' the outer corona with gradually
reduced perihelia from its first perihelia of 35 Rs in 2018-19 to 9.8
Rs in 2025. Here we report the results from the imaging observations
of the electron and dust corona, whe PSP was 35-54 Rs from the solar
surface, taken by the Wide-field Imager for Solar Probe (WISPR). The
spacecraft was near-corotating with the solar corona throughout the
observing window, which is an unprecedented situation for any type of
coronal imaging. Our initial analysis uncovers a long-hypothesized
depletion of the primordial dust orbiting near the Sun, reveals the
plasma structure of small-scale ejections, and provides a strict test
for validating model predictions of the large-scale configuration of
the coronal plasma. Thus, WISPR imaging allows the study of near-Sun
dust dynamics as the mission progresses. The high-resolution images
of small transients, largely unresolved from 1 AU orbits, unravel
the sub-structures of small magnetic flux ropes and show that the
Sun continually releases helical magnetic fields in the background
wind. Finally, WISPR's observations of the coronal streamer evolution
confirm the large-scale topology of the solar corona but they also
reveal that, as recently predicted, streamers are composed of yet
smaller sub-streamers channeling continual density fluctuations at
all visible scales.
---------------------------------------------------------
Title: The Solar Polar Observing Constellation (SPOC) Mission:
research and operational monitoring of space weather from polar
heliocentric orbits
Authors: Berger, T. E.; Bosanac, N.; Smith, T. R.; Duncan, N. A.;
Wu, G.; Turner, E.; Hurlburt, N.; Korendyke, C.
2019AGUFMSH43F3352B Altcode:
The Sun's polar regions remain largely unobserved and yet understanding
and monitoring of the magnetic field, convective flows, and coronal
outflow conditions in the solar polar regions are the keys to accurately
modeling and forecasting the solar cycle, solar wind conditions,
and CME arrival times at Earth. We describe the Solar Polar Observing
Constellation (SPOC), a mission to establish continuous high-resolution
imaging of solar magnetic field dynamics, high-latitude surface and
sub-surface convective flows, and coronal mass ejection tracking from
a low-eccentricity polar heliocentric orbit. SPOC will consist of two
identical spacecraft, each equipped with a Lockheed Martin Compact
Magnetic Imager (CMI, derived from the Solar Dynamics Observatory
(SDO) Helioseismic and Magnetic Imager), the Naval Research Laboratory
(NRL) Compact Coronagraph (CCOR), and in-situ solar wind and energetic
particle instruments. Falcon Heavy launch vehicles will place the
SPOC spacecraft into a Jupiter gravitational assist (JGA) heliocentric
orbit, achieving an 88-degree ecliptic inclination, with the spacecraft
passing over the solar poles within 4 years after launch. Ion engines
will subsequently reduce the eccentricity of the orbits to below 0.05
at approximately 0.9 AU within 6 years after launch. Orbital phasing
will place the spacecraft over alternate poles to enable continuous
monitoring of the polar regions with operational-level redundancy of
systems. The inclusion of CCOR will enable visualization and tracking
of coronal mass ejections from above (or below) the ecliptic for the
first time, greatly enhancing our ability to forecast CME arrival times
at Earth and other planets such as Mars. SPOC combines polar region
exploration, high-latitude helioseismology and magnetic imaging, and
operational space weather monitoring in a single mission. Along with
planned missions to the L1 and L5 Lagrangian points in the ecliptic,
SPOC will enable an approach to the long-sought goal of continuous
full-sphere measurements of the solar magnetic field, solar wind and CME
outflow, and energetic particle flux - a goal that cannot be achieved
with observations from the ecliptic plane alone.
---------------------------------------------------------
Title: The Solar Orbiter Heliospheric Imager (SoloHI) for the Solar
Orbiter Mission: Science and Instrument Status
Authors: Vourlidas, A.; Howard, R. A.; Colaninno, R. C.; Korendyke,
C.; Thernisien, A.; Linton, M.; Tun Beltran, S.; Liewer, P. C.; Velli,
M.; Linker, J.; Bothmer, V.; Rochus, P. L.; Lamy, P. L.
2019AGUFMSH24A..08V Altcode:
The SoloHI instrument has completed its development effort and has been
integrated onto the Solar Orbiter spacecraft. The mission, scheduled
for launch in February 2020, will undergo gravity assist maneuvers
around Venus to change both the perihelion distance as well as the
plane of the orbit to ultimately achieve a minimum perihelion of 0.28
AU and an orbital inclination of about 35° relative to the ecliptic
plane. The remote sensing instruments will operate for three 10-day
periods out of the nominal 6-month orbit. SoloHI detects sunlight
scattered by free electrons in the corona and solar wind from 5° to
45° elongation in visible wavelengths, providing linkage between solar
and solar wind observations. The science investigation focuses mainly on
the solar wind, including streamers, small-scale intensity and density
fluctuations, jets, and Coronal Mass Ejections (CMEs). SoloHI is very
similar to the HI-1 instrument on STEREO/SECCHI but with double the FOV
of HI-1. In this paper, we present our preparations for the mission
including the instrument status, our science planning strategy, our
observing plans for cruise phase, calibrations, early science and our
low-latency and science data products <P />This work has been supported
by NASA.
---------------------------------------------------------
Title: Near-Sun observations of an F-corona decrease and K-corona
fine structure
Authors: Howard, R. A.; Vourlidas, A.; Bothmer, V.; Colaninno, R. C.;
DeForest, C. E.; Gallagher, B.; Hall, J. R.; Hess, P.; Higginson,
A. K.; Korendyke, C. M.; Kouloumvakos, A.; Lamy, P. L.; Liewer, P. C.;
Linker, J.; Linton, M.; Penteado, P.; Plunkett, S. P.; Poirier, N.;
Raouafi, N. E.; Rich, N.; Rochus, P.; Rouillard, A. P.; Socker, D. G.;
Stenborg, G.; Thernisien, A. F.; Viall, N. M.
2019Natur.576..232H Altcode:
Remote observations of the solar photospheric light scattered by
electrons (the K-corona) and dust (the F-corona or zodiacal light)
have been made from the ground during eclipses<SUP>1</SUP> and from
space at distances as small as 0.3 astronomical units<SUP>2-5</SUP> to
the Sun. Previous observations<SUP>6-8</SUP> of dust scattering have
not confirmed the existence of the theoretically predicted dust-free
zone near the Sun<SUP>9-11</SUP>. The transient nature of the corona
has been well characterized for large events, but questions still
remain (for example, about the initiation of the corona<SUP>12</SUP>
and the production of solar energetic particles<SUP>13</SUP>) and
for small events even its structure is uncertain<SUP>14</SUP>. Here
we report imaging of the solar corona<SUP>15</SUP> during the first
two perihelion passes (0.16-0.25 astronomical units) of the Parker
Solar Probe spacecraft<SUP>13</SUP>, each lasting ten days. The view
from these distances is qualitatively similar to the historical views
from ground and space, but there are some notable differences. At
short elongations, we observe a decrease in the intensity of the
F-coronal intensity, which is suggestive of the long-sought dust
free zone<SUP>9-11</SUP>. We also resolve the fine-scale plasma
structure of very small eruptions, which are frequently ejected from
the Sun. These take two forms: the frequently observed magnetic flux
ropes<SUP>12,16</SUP> and the predicted, but not yet observed, magnetic
islands<SUP>17,18</SUP> arising from the tearing-mode instability in
the current sheet. Our observations of the coronal streamer evolution
confirm the large-scale topology of the solar corona, but also reveal
that, as recently predicted<SUP>19</SUP>, streamers are composed of
yet smaller substreamers channelling continual density fluctuations
at all visible scales.
---------------------------------------------------------
Title: Concept study of Solar-C_EUVST optical design
Authors: Kawate, Tomoko; Shimizu, Toshifumi; Imada, Shinsuke; Tsuzuki,
Toshihiro; Katsukawa, Yukio; Hara, Hirohisa; Suematsu, Yoshinori;
Ichimoto, Kiyoshi; Warren, Harry; Teriaca, Luca; Korendyke, Clarence
M.; Brown, Charles
2019SPIE11118E..1NK Altcode:
The main characteristics of Solar-C_EUVST are the high temporal and
high spatial resolutions over a wide temperature coverage. In order
to realize the instrument for meeting these scientific requirements
under size constraints given by the JAXA Epsilon vehicle, we examined
four-dimensional optical parameter space of possible solutions of
geometrical optical parameters such as mirror diameter, focal length,
grating magnification, and so on. As a result, we have identified
the solution space that meets the EUVST science objectives and rocket
envelope requirements. A single solution was selected and used to define
the initial optical parameters for the concept study of the baseline
architecture for defining the mission concept. For this solution, we
optimized the grating and geometrical parameters by ray tracing of the
Zemax software. Consequently, we found an optics system that fulfills
the requirement for a 0.4" angular resolution over a field of view of
100" (including margins) covering spectral ranges of 170-215, 463-542,
557-637, 690-850, 925-1085, and 1115-1275 A. This design achieves an
effective area 10 times larger than the Extreme-ultraviolet Imaging
Spectrometer onboard the Hinode satellite, and will provide seamless
observations of 4.2-7.2 log(K) plasmas for the first time. Tolerance
analyses were performed based on the optical design, and the moving
range and step resolution of focus mechanisms were identified. In
the presentation, we describe the derivation of the solution space,
optimization of the optical parameters, and show the results of ray
tracing and tolerance analyses.
---------------------------------------------------------
Title: The Solar-C_EUVST mission
Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kawate, Tomoko;
Ichimoto, Kiyoshi; Suematsu, Yoshinori; Hara, Hirohisa; Katsukawa,
Yukio; Kubo, Masahito; Toriumi, Shin; Watanabe, Tetsuya; Yokoyama,
Takaaki; Korendyke, Clarence M.; Warren, Harry P.; Tarbell, Ted; De
Pontieu, Bart; Teriaca, Luca; Schühle, Udo H.; Solanki, Sami; Harra,
Louise K.; Matthews, Sarah; Fludra, A.; Auchère, F.; Andretta, V.;
Naletto, G.; Zhukov, A.
2019SPIE11118E..07S Altcode:
Solar-C EUVST (EUV High-Throughput Spectroscopic Telescope) is a
solar physics mission concept that was selected as a candidate for
JAXA competitive M-class missions in July 2018. The onboard science
instrument, EUVST, is an EUV spectrometer with slit-jaw imaging
system that will simultaneously observe the solar atmosphere from the
photosphere/chromosphere up to the corona with seamless temperature
coverage, high spatial resolution, and high throughput for the first
time. The mission is designed to provide a conclusive answer to the
most fundamental questions in solar physics: how fundamental processes
lead to the formation of the solar atmosphere and the solar wind, and
how the solar atmosphere becomes unstable, releasing the energy that
drives solar flares and eruptions. The entire instrument structure
and the primary mirror assembly with scanning and tip-tilt fine
pointing capability for the EUVST are being developed in Japan, with
spectrograph and slit-jaw imaging hardware and science contributions
from US and European countries. The mission will be launched and
installed in a sun-synchronous polar orbit by a JAXA Epsilon vehicle in
2025. ISAS/JAXA coordinates the conceptual study activities during the
current mission definition phase in collaboration with NAOJ and other
universities. The team is currently working towards the JAXA final
down-selection expected at the end of 2019, with strong support from
US and European colleagues. The paper provides an overall description
of the mission concept, key technologies, and the latest status.
---------------------------------------------------------
Title: Element Abundances: A New Diagnostic for the Solar Wind
Authors: Laming, J. Martin; Vourlidas, Angelos; Korendyke, Clarence;
Chua, Damien; Cranmer, Steven R.; Ko, Yuan-Kuen; Kuroda, Natsuha;
Provornikova, Elena; Raymond, John C.; Raouafi, Nour-Eddine; Strachan,
Leonard; Tun-Beltran, Samuel; Weberg, Micah; Wood, Brian E.
2019ApJ...879..124L Altcode: 2019arXiv190509319L
We examine the different element abundances exhibited by the closed
loop solar corona and the slow speed solar wind. Both are subject
to the first ionization potential (FIP) effect, the enhancement in
coronal abundance of elements with FIP below 10 eV (e.g., Mg, Si,
Fe) with respect to high-FIP elements (e.g., O, Ne, Ar), but with
subtle differences. Intermediate elements, S, P, and C, with FIP
just above 10 eV, behave as high-FIP elements in closed loops, but
are fractionated more like low-FIP elements in the solar wind. On
the basis of FIP fractionation by the ponderomotive force in the
chromosphere, we discuss fractionation scenarios where this difference
might originate. Fractionation low in the chromosphere where hydrogen
is neutral enhances the S, P, and C abundances. This arises with
nonresonant waves, which are ubiquitous in open field regions, and is
also stronger with torsional Alfvén waves, as opposed to shear (i.e.,
planar) waves. We discuss the bearing these findings have on models
of interchange reconnection as the source of the slow speed solar
wind. The outflowing solar wind must ultimately be a mixture of the
plasma in the originally open and closed fields, and the proportions
and degree of mixing should depend on details of the reconnection
process. We also describe novel diagnostics in ultraviolet and extreme
ultraviolet spectroscopy now available with these new insights, with
the prospect of investigating slow speed solar wind origins and the
contribution of interchange reconnection by remote sensing.
---------------------------------------------------------
Title: Stray light analysis and testing of the SoloHI (solar orbiter
heliospheric imager) and WISPR (wide field imager for solar probe)
heliospheric imagers
Authors: Thernisien, Arnaud F. R.; Howard, Russell A.; Korendyke,
Clarence; Carter, Tim; Chua, Damien; Plunkett, Simon
2018SPIE10698E..0ET Altcode:
The techniques for stray light analysis, optimization and testing
are described for two space telescopes that observe the solar corona:
the Solar Orbiter Heliospheric Imager (SoloHI) that will fly on the ESA
Solar Orbiter (SolO), and the Wide Field Imager for Solar Probe (WISPR)
that will fly on the NASA Parker Solar Probe (PSP) mission. Imaging
the solar corona is challenging, because the corona is six orders of
magnitude dimmer than the Sun surface at the limb, and the coronal
brightness continues to decrease to ten orders of magnitude below
the Sun limb above 5° elongation from Sun center. The SoloHI and
WISPR instruments are located behind their respective spacecraft heat
shield. Each spacecraft heat shield does not block the instrument
field of view above the solar limb, but will prevent direct sunlight
entering the instrument aperture. To satisfy the instrument stray light
attenuation required to observe the solar corona, an additional set of
instrument baffles were designed and tested for successive diffraction
of the heat shield diffracted light before entering the telescope
entrance pupil. A semi empirical model of diffraction was used to
design the baffles, and tests of the flight models were performed in
flight like conditions with the aim of verifying the rejection of the
design. Test data showed that the baffle systems behaved as expected. A
second source of stray light is due to reflections of the sunlight
off of the spacecraft structures and towards the instruments. This is
especially the case for SoloHI where one of the spacecraft 8m tall
solar arrays is located behind the telescope and reflects sunlight
back onto the instrument baffles. The SoloHI baffle design had to be
adjusted to mitigate that component, which was achieved by modifying
their geometry and their optical coating. Laboratory tests of the
flight model were performed. The test data were correlated with the
predictions of a ray tracing model, which enabled the fine tuning of
the model. Finally, end-to-end ray tracing was used to predict the
stray light for the flight conditions.
---------------------------------------------------------
Title: Global Magnetospheric Imaging from the Deep Space Gateway in
Lunar Orbit
Authors: Chua, Damien H.; Socker, Dennis G.; Englert, Christoph R.;
Carter, Michael T.; Plunkett, Simon P.; Korendyke, Clarence; Meier,
Robert
2018tess.conf21265C Altcode:
We propose to use the Deep Space Gateway (DSG) in lunar orbit as an
observing platform for a magnetospheric imager that will capture the
first direct global images of the interface between the incident solar
wind and the Earth's magnetosphere, and the response of the coupled
magnetosphere-plasmasphere-ionosphere system to all incident solar
plasmas. The optical detection of the faint magnetosphere surrounding
the bright Earth is achieved using the same techniques as those used
to image the faint solar corona and solar wind. This method measures
the brightness of visible that is Thomson-scattered by electrons in the
solar wind and magnetospheric plasmas. The Thomson scattering brightness
is proportional to the line of sight column electron density. The
large-scale context afforded by globally imaging the magnetosphere
promises major advances in our fundamental understanding of solar wind
driving of the magnetosphere. Such images would reveal how electrons
in the magnetosphere and plasmasphere are redistributed in response
to solar wind forcing, particularly when CMEs and CIRs interact with
geospace. Global images of the magnetosphere would also be useful
for proving global boundary conditions to ionospheric specification
models. Our global magnetospheric imager on DSG would be implemented
as an externally mounted instrument suite that would not require any
crew interaction under normal operation. The instrument suite would
consist of an Earth-centered geocoronagraph (analogous to a solar
coronagraph) with an external occulter of radius 1.2 - 1.5 Earth radii
(R<SUB>E</SUB>) and a magnetospheric imager (analogous to a heliospheric
imager). A geocoronagraph with an Earth-centered field of view of
25° would observe out to 26 R<SUB>E</SUB> from lunar orbit. This
is sufficient to observe the entire cross section of the dayside
magnetosphere, including the bow shock and magnetopause, the polar
cusps, and a significant portion of the tail lobes. The magnetospheric
imager would have an overlapping field of view approximately 30° wide
that could be pointed upstream of the magnetosphere to image solar
wind structures approaching the magnetosphere or downstream of Earth
to observe the dynamics of the magnetotail plasma sheet.
---------------------------------------------------------
Title: Global Magnetospheric Imaging from the Deep Space Gateway in
Lunar Orbit
Authors: Chua, D. H.; Socker, D. G.; Englert, C. R.; Carter, M. T.;
Plunkett, S. P.; Korendyke, C. M.; Meier, R. R.
2018LPICo2063.3161C Altcode:
We propose to use the Deep Space Gateway as an observing platform
for a magnetospheric imager that will capture the first direct global
images of the interface between the incident solar wind and the Earth's
magnetosphere.
---------------------------------------------------------
Title: Using the Deep Space Gateway to Build the Next Generation
Heliophysics Research Grid
Authors: Vourlidas, A.; Ho, G. C.; Cohen, I. J.; Korendyke, C. M.;
Tun-Beltran, S.; Plunkett, S. P.; Newmark, J.; St Cyr, O. C.;
Hoeksema, T.
2018LPICo2063.3055V Altcode:
The Heliophysics Research Grid (HRG) consists of in situ and imaging
sensors, distributed in key locations in the heliosphere for research
and to support space exploration needs. The Deep Space Gateway enables
the HRG as a storage and staging hub for HRG launches.
---------------------------------------------------------
Title: The Solar Orbiter Heliospheric Imager (SoloHI) for the Solar
Orbiter Mission
Authors: Howard, R.; Colaninno, R. C.; Plunkett, S. P.; Thernisien,
A. F.; Wang, D.; Rich, N.; Korendyke, C.; Socker, D. G.; Linton, M.;
McMullin, D. R.; Vourlidas, A.; Liewer, P. C.; De Jong, E.; Velli,
M.; Mikic, Z.; Bothmer, V.; Philippe, L.; Carter, M. T.
2017AGUFMSH23D2681H Altcode:
The SoloHI instrument has completed its development effort and has been
integrated onto the Solar Orbiter (SolO) spacecraft. The SolO mission,
scheduled for launch in February 2019, will undergo gravity assist
maneuvers around Venus to change both the perihelion distance as well
as the plane of the orbit to ultimately achieve a minimum perihelion
of 0.28 AU and an orbital inclination of about 35° relative to the
ecliptic plane. The remote sensing instruments will operate for three
10-day periods out of the nominal 6-month orbit. SoloHI will observe
sunlight scattered by free electrons in the corona/solar wind from 5°
to 45° elongation in visible wavelengths and will provide a coupling
between remote sensing and in situ observations. It is very similar
to the HI-1 instrument on STEREO/SECCHI except that the FOV is twice
the size at 40o. We present our efforts to prepare for the mission
including our observing plans, quick-look plans and some results of
the calibration activities. We gratefully acknowledge the support of
the NASA Solar Orbiter Collaboration project.
---------------------------------------------------------
Title: The Wide-Field Imager for the Parker Solar Probe Mission
(WISPR)
Authors: Plunkett, S. P.; Howard, R.; Chua, D. H.; Crump, N. A.;
Dennison, H.; Korendyke, C.; Linton, M.; Rich, N.; Socker, D. G.;
Thernisien, A. F.; Wang, D.; Vourlidas, A.; Baugh, R.; Van Duyne,
J. P.; Liewer, P. C.; De Jong, E.; Boies, M. T.; Mikic, Z.; Bothmer,
V.; Rochus, P.; Halain, J. P.
2017AGUFMSH23D2693P Altcode:
The Parker Solar Probe (PSP) mission will be humanity's first visit
to the atmosphere of our nearest star, the Sun, when it is launched
in July 2018. PSP will complete 24 orbits between the Sun and Venus
with diminishing perihelia reaching as close as 7 million km (9.86
solar radii) from Sun center. In addition to a suite of in-situ probes
for the magnetic field, plasma, and energetic particles, the payload
includes the Wide Field Imager for Solar Probe (WISPR) that will
record unprecedented visible light images of the solar corona and the
inner heliosphere. WISPR is the smallest heliospheric imager to date,
and comprises two nested wide-field telescopes with large-format (2K
x 2K) APS CMOS detectors to optimize the performance over a combined
95º radial by 58º transverse field of view and to minimize the risk
of dust damage, which may be considerable close to the Sun. WISPR will
discover - in this never-before explored region of the heliosphere - the
fundamental nature of coronal structures and the source regions of the
solar wind as the PSP flies through them, and will determine whether a
dust-free zone exists near the Sun. WISPR has completed its development
effort and has been integrated onto the PSP spacecraft. In this paper,
we will present our efforts to prepare for the mission including our
observing plans and some results of the calibration activities.
---------------------------------------------------------
Title: Stray light testing of WISPR baffle development model
Authors: Hellin, M. -L.; Mazy, E.; Marcotte, S.; Stockman, Y.;
Korendyke, C.; Thernisien, A.
2017SPIE10562E..4VH Altcode:
Solar Probe Plus (SPP) is a NASA mission developed to visit and study
the sun closer than ever before. SPP is designed to orbit as close as 7
million km (9.86 solar radii) from Sun center. One of its instruments:
WISPR (Wide-Field Imager for Solar Probe Plus) will be the first `local'
imager to provide the relation between the large-scale corona and the
in-situ measurements.
---------------------------------------------------------
Title: The Ultraviolet Spectro-Coronagraph (UVSC) Pathfinder
Experiment for the Remote Detection of Suprathermal Seed Particles:
Instrument Status
Authors: Strachan, Leonard; Laming, J. Martin; Ko, Yuan-Kuen; Tun
Beltran, Samuel; Korendyke, Clarence M.; Brown, Charles M.; Socker,
Dennis G.; Galysh, Ivan J.; Finne, Theodore T.; Eisenhower, Kevin
C.; Brechbiel, David J.; Noya, Mario; Provornikova, Elena; Gardner,
Larry D.
2017SPD....4811007S Altcode:
The largest solar energetic particle (SEP) storms are produced by
fast coronal mass ejection (CME) shocks. Efficient shock acceleration
of ambient particles requires a near sun reservoir of suprathermal
(proton) seed particles. However, the requisite seed particle
reservoir has not been detected near the sun where CME shocks first
appear. We are developing the Ultraviolet Spectro-Coronagraph (UVSC)
Pathfinder space experiment to test for the presence or absence of
the requisite suprathermal proton seed particle population within 3
solar radii of sun-center. In this poster, we present the instrument
design concept, its development status, and the expected experimental
results. The ultimate goal for the experiment is to demonstrate how
such measurements can be used as a part of a future SEP space weather
warning system. UVSC Pathfinder is scheduled to be launched in 2019 by
the DoD Space Test Program. It is supported by funds from the Chief
of Naval Research (via the NRL basic research program) and from NASA
(via NDPR NNG13WF951 and NNH16AC29I).
---------------------------------------------------------
Title: LOCKYER (Large Optimized Coronagraph for KeY Emission line
Research): A SMEX Mission to Provide Crucial Measurements of the
Genesis of the Solar Wind and CMEs
Authors: Ko, Y. K.; Vourlidas, A.; Korendyke, C.; Laming, J. M.
2016AGUFMSH43B2569K Altcode:
The LOCKYER mission is designed to uncover the physical processes of
acceleration and heating of the quiescent and transient solar wind. It
builds on the success of the Ultraviolet Coronagraph Spectrometer
(UVCS) on SOHO with a massive increase in effective area at Lyman-alpha
(200x larger than UVCS), thanks to a modern optical design and the
use of a 4m boom. The larger effective area enables spectral line
observations from many ions, including He II (at 1640 Å), allowing us
to access the region where the coronal plasma transitions from fluid
to kinetic behavior. In addition, a visible light channel provides
simultaneous high-resolution coronagraphic images for the global
coronal structure and dynamics creating a greatly-expanded UVCS-LASCO
`hybrid' instrument within the tight constraints of a SMEX mission. The
LOCKYER mission aims to answer the following questions: 1) What are
the physical processes responsible for the heating and acceleration
of the primary (proton, electron, helium) and secondary (minor ion)
plasma components of the fast and slow solar wind? 2) How are CMEs
heated and accelerated? LOCKYER would greatly advance our knowledge
of how and where the solar wind is formed, and how the variations in
coronal microphysics impact the solar wind and heliosphere. The LOCKYER
measurements are highly complementary to the Solar Probe Plus and Solar
Orbiter measurements and provide detailed empirical descriptions of
the coronal plasma at heights where the primary energy and momentum
addition occur.
---------------------------------------------------------
Title: The Wide-Field Imager for Solar Probe Plus (WISPR)
Authors: Vourlidas, Angelos; Howard, Russell A.; Plunkett, Simon P.;
Korendyke, Clarence M.; Thernisien, Arnaud F. R.; Wang, Dennis; Rich,
Nathan; Carter, Michael T.; Chua, Damien H.; Socker, Dennis G.; Linton,
Mark G.; Morrill, Jeff S.; Lynch, Sean; Thurn, Adam; Van Duyne, Peter;
Hagood, Robert; Clifford, Greg; Grey, Phares J.; Velli, Marco; Liewer,
Paulett C.; Hall, Jeffrey R.; DeJong, Eric M.; Mikic, Zoran; Rochus,
Pierre; Mazy, Emanuel; Bothmer, Volker; Rodmann, Jens
2016SSRv..204...83V Altcode: 2015SSRv..tmp....8V; 2015SSRv..tmp...66B
The Wide-field Imager for Solar PRobe Plus (WISPR) is the sole imager
aboard the Solar Probe Plus (SPP) mission scheduled for launch in
2018. SPP will be a unique mission designed to orbit as close as
7 million km (9.86 solar radii) from Sun center. WISPR employs a
95<SUP>∘</SUP> radial by 58<SUP>∘</SUP> transverse field of view
to image the fine-scale structure of the solar corona, derive the 3D
structure of the large-scale corona, and determine whether a dust-free
zone exists near the Sun. WISPR is the smallest heliospheric imager to
date yet it comprises two nested wide-field telescopes with large-format
(2 K × 2 K) APS CMOS detectors to optimize the performance for their
respective fields of view and to minimize the risk of dust damage,
which may be considerable close to the Sun. The WISPR electronics are
very flexible allowing the collection of individual images at cadences
up to 1 second at perihelion or the summing of multiple images to
increase the signal-to-noise when the spacecraft is further from the
Sun. The dependency of the Thomson scattering emission of the corona
on the imaging geometry dictates that WISPR will be very sensitive
to the emission from plasma close to the spacecraft in contrast to
the situation for imaging from Earth orbit. WISPR will be the first
`local' imager providing a crucial link between the large-scale corona
and the in-situ measurements.
---------------------------------------------------------
Title: The Ultraviolet Spectro-Coronagraph Pathfinder Mission for
the Detection of Coronal Suprathermal Seed Particles
Authors: Strachan, Leonard; Laming, J. Martin; Ko, Yuan-Kuen;
Korendyke, Clarence M.; Tun Beltran, Samuel; Socker, Dennis G.; Brown,
Charles; Provornikova, Elena
2016SPD....4730104S Altcode:
The Ultraviolet Spectro-Coronagraph (UVSC) Pathfinder is a Naval
Research Laboratory experiment designed to make the first detection
of suprathermal seed particles close to the Sun. It uses an innovative
“stacked” occulting system to significantly increase the effective
light gathering power of a traditional, 1-meter length, externally
occulted coronagraph. The external occultation in combination with a low
scatter variable line spaced grating provide the stray light suppression
needed to measure non-Maxwellian departures in the wings of the H Lyman
alpha emission line profile. After the removal of other factors, these
departures may be interpreted as the signature of suprathermal tails of
the proton velocity distribution in the corona. UVSC Pathfinder will
provide information on the origins and spatial/temporal variability
of proton seed particle populations. We will discuss the accuracy
needed to make such measurements and describe how the results can
be used to develop a capability for predicting the onset of Solar
Energetic Particle (SEP) storms. The experiment is scheduled for
a launch by the DoD Space Test Program in late 2018/early 2019 and
should have excellent overlap with the Solar Orbiter and Solar Probe
Plus missions.UVSC Pathfinder is supported by funds from the Chief
of Naval Research (via the NRL basic research program) and from NASA
(via NDPR NNG13WF951 and NNH16AC29I).
---------------------------------------------------------
Title: Investigation of the Chromosphere-Corona Interface with the
Upgraded Very High Angular Resolution Ultraviolet Telescope (VAULT2.0)
Authors: Vourlidas, Angelos; Beltran, Samuel Tun; Chintzoglou,
Georgios; Eisenhower, Kevin; Korendyke, Clarence; Feldman, Ronen;
Moser, John; Shea, John; Johnson-Rambert, Mary; McMullin, Don;
Stenborg, Guillermo; Shepler, Ed; Roberts, David
2016JAI.....540003V Altcode:
Very high angular resolution ultraviolet telescope (VAULT2.0) is a
Lyman-alpha (Lyα; 1216Å) spectroheliograph designed to observe
the upper chromospheric region of the solar atmosphere with high
spatial (<0.5‧‧) and temporal (8s) resolution. Besides being
the brightest line in the solar spectrum, Lyα emission arises at
the temperature interface between coronal and chromospheric plasmas
and may, hence, hold important clues about the transfer of mass and
energy to the solar corona. VAULT2.0 is an upgrade of the previously
flown VAULT rocket and was launched successfully on September 30, 2014
from White Sands Missile Range (WSMR). The target was AR12172 midway
toward the southwestern limb. We obtained 33 images at 8s cadence at
arc second resolution due to hardware problems. The science campaign
was a resounding success, with all space and ground-based instruments
obtaining high-resolution data at the same location within the AR. We
discuss the science rationale, instrument upgrades, and performance
during the first flight and present some preliminary science results.
---------------------------------------------------------
Title: Waves and Magnetism in the Solar Atmosphere (WAMIS)
Authors: Ko, Yuan-Kuen; Moses, John; Laming, John; Strachan, Leonard;
Tun Beltran, Samuel; Tomczyk, Steven; Gibson, Sarah; Auchere, Frederic;
Casini, Roberto; Fineschi, Silvano; Knoelker, Michael; Korendyke,
Clarence; McIntosh, Scott; Romoli, Marco; Rybak, Jan; Socker, Dennis;
Vourlidas, Angelos; Wu, Qian
2016FrASS...3....1K Altcode:
Comprehensive measurements of magnetic fields in the solar corona have
a long history as an important scientific goal. Besides being crucial
to understanding coronal structures and the Sun’s generation of space
weather, direct measurements of their strength and direction are also
crucial steps in understanding observed wave motions. In this regard,
the remote sensing instrumentation used to make coronal magnetic field
measurements is well suited to measuring the Doppler signature of waves
in the solar structures. In this paper, we describe the design and
scientific values of the Waves and Magnetism in the Solar Atmosphere
(WAMIS) investigation. WAMIS, taking advantage of greatly improved
infrared filters and detectors, forward models, advanced diagnostic
tools and inversion codes, is a long-duration high-altitude balloon
payload designed to obtain a breakthrough in the measurement of
coronal magnetic fields and in advancing the understanding of the
interaction of these fields with space plasmas. It consists of a 20 cm
aperture coronagraph with a visible-IR spectro-polarimeter focal plane
assembly. The balloon altitude would provide minimum sky background and
atmospheric scattering at the wavelengths in which these observations
are made. It would also enable continuous measurements of the strength
and direction of coronal magnetic fields without interruptions from
the day-night cycle and weather. These measurements will be made
over a large field-of-view allowing one to distinguish the magnetic
signatures of different coronal structures, and at the spatial and
temporal resolutions required to address outstanding problems in
coronal physics. Additionally, WAMIS could obtain near simultaneous
observations of the electron scattered K-corona for context and to
obtain the electron density. These comprehensive observations are not
provided by any current single ground-based or space observatory. The
fundamental advancements achieved by the near-space observations of
WAMIS on coronal field would point the way for future ground based
and orbital instrumentation.
---------------------------------------------------------
Title: Waves and Magnetism in the Solar Atmosphere (WAMIS)
Authors: Strachan, L.; Ko, Y. -K.; Moses, J. D.; Laming, J. M.;
Auchere, F.; Casini, R.; Fineschi, S.; Gibson, S.; Knoelker, M.;
Korendyke, C.; Mcintosh, S.; Romoli, M.; Rybak, J.; Socker, D.;
Tomczyk, S.; Vourlidas, A.; Wu, Q.
2015IAUS..305..121S Altcode:
Magnetic fields in the solar atmosphere provide the energy for most
varieties of solar activity, including high-energy electromagnetic
radiation, solar energetic particles, flares, and coronal mass
ejections, as well as powering the solar wind. Despite the fundamental
role of magnetic fields in solar and heliospheric physics, there
exist only very limited measurements of the field above the base of
the corona. What is needed are direct measurements of not only the
strength and orientation of the magnetic field but also the signatures
of wave motions in order to better understand coronal structure, solar
activity, and the role of MHD waves in heating and accelerating the
solar wind. Fortunately, the remote sensing instrumentation used to make
magnetic field measurements is also well suited to measure the Doppler
signature of waves in the solar structures. We present here a mission
concept for the Waves And Magnetism In the Solar Atmosphere (WAMIS)
experiment which is proposed for a NASA long-duration balloon flight.
---------------------------------------------------------
Title: The VAULT2.0 Observing Campaign: A Comprehensive Investigation
of the Chromosphere-Corona Interface at Sub-arcsecond scales
Authors: Vourlidas, A.; Korendyke, C.; Tun-Beltran, S. D.; Ugarte-Urra,
I.; Morrill, J. S.; Warren, H. P.; Young, P.; De Pontieu, B.; Gauzzi,
G.; Reardon, K.
2014AGUFMSH41C4155V Altcode:
We report the first results from an observing campaign in support of
the VAULT2.0 sounding rocket launch on September 30, 2014. VAULT2.0
is a Lya (1216Å) spectroheliograph capable of 0.3" (~250 km) spatial
resolution. The objective of the VAULT2.0 project is the study of
the chromosphere-corona interface. This interface has acquired renewed
emphasis over the last few years, thanks to high-resolution observations
from Hinode/SOT and EIS instruments and the Lya imaging from the two
VAULT flights. The observations have shown that the upper chromosphere
may play a more important role in heating the corona and in affecting
EUV observations that previously thought: (1) by supplying the mass
via Type-II spicules and, (2) by absorbing coronal emission. Many of
the required clues for further progress are located in sub-arcsecond
structures with temperatures between 10000 and 50000 K, a regime not
accessible by Hinode or SDO. Lyman-alpha observations are, therefore,
ideal, for filling in this gap. The observing campaign in support of
the VAULT2.0 is closely coordinated with the Hinode and IRIS missions
to study the mass/energy flow from the chromosphere to the corona with
joint observations of type-II spicules, and the magnetic connectivity
of coronal loops using the full imaging and spectral capabilities of
IRIS, Hinode and SDO. Several ground-based observatories also provide
important observations (IBIS, BBSO, SOLIS). The VAULT2.0 project is
funded by the NASA LCAS program.
---------------------------------------------------------
Title: Observations of Near-Sun Turbulent Density Fluctuations with
the Wide Field Imager for Solar Probe Plus (WISPR)
Authors: Plunkett, S. P.; Howard, R.; Vourlidas, A.; Korendyke, C.;
Rich, N.; Thernisien, A. F.; Wang, D.; Liewer, P. C.
2014AGUFMSH32A..05P Altcode:
The trajectory of Solar Probe Plus (SPP) as it transits through
the solar corona with a perihelion of < 10 Rs will allow much
higher contrast observations of small-scale density fluctuations
with higher cadence than is possible from 1 AU. The WISPR instrument
will implement a high-cadence mode (up to 1 second) in which it will
obtain images of the corona and inner heliosphere with high spatial
resolution over a restricted field of view around specified regions of
interest. Two-dimensional power spectra of the density fluctuations
can then be constructed with variable cadences for direct comparison
to similar spectra obtained by in-situ instruments on SPP and Solar
Orbiter (SO). WISPR will provide density power spectra at or below
the spectral break between inertial and injection scales, even at the
closest perihelion approach, for different coronal structures. When
combined with tomographic information from synoptic images, the
WISPR turbulence program will be a major enhancement to the turbulence
measurements from the SPP and SO in-situ instruments resulting in a much
more robust understanding of the near-Sun turbulence. We will present
details of the planned observations and will discuss the coordinated
science objectives that can be addressed using these observations.
---------------------------------------------------------
Title: Waves and Magnetism in the Solar Atmosphere (WAMIS)
Authors: Ko, Y. K.; Auchere, F.; Casini, R.; Fineschi, S.; Gibson,
S. E.; Knoelker, M.; Korendyke, C.; Laming, J. M.; Mcintosh, S. W.;
Moses, J. D.; Romoli, M.; Rybak, J.; Socker, D. G.; Strachan, L.;
Tomczyk, S.; Vourlidas, A.; Wu, Q.
2014AGUFMSH53B4221K Altcode:
Magnetic fields in the solar atmosphere provide the energy for most
varieties of solar activity, including high-energy electromagnetic
radiation, solar energetic particles, flares, and coronal mass
ejections, as well as powering the solar wind. Despite the fundamental
role of magnetic fields in solar and heliospheric physics, there
exists only very limited measurements of the field above the base of
the corona. What is needed are direct measurements of not only the
strength and orientation of the magnetic field but also the signatures
of wave motions in order to better understand coronal structure,
solar activity and the role of MHD waves in heating and accelerating
the solar wind. Fortunately, the remote sensing instrumentation used
to make magnetic field measurements is also well suited for measuring
the Doppler signature of waves in the solar structures. With this
in mind, we are proposing the WAMIS (Waves and Magnetism in the
Solar Atmosphere) investigation. WAMIS will take advantage of greatly
improved infrared (IR) detectors, forward models, advanced diagnostic
tools and inversion codes to obtain a breakthrough in the measurement
of coronal magnetic fields and in the understanding of the interaction
of these fields with space plasmas. This will be achieved with a high
altitude balloon borne payload consisting of a coronagraph with an IR
spectro-polarimeter focal plane assembly. The balloon platform provides
minimum atmospheric absorption and scattering at the IR wavelengths in
which these observations are made. Additionally, a NASA long duration
balloon flight mission from the Antarctic can achieve continuous
observations over most of a solar rotation, covering all of the key
time scales for the evolution of coronal magnetic fields. With these
improvements in key technologies along with experience gained from
current ground-based instrumentation, WAMIS will provide a low-cost
mission with a high technology readiness leve.
---------------------------------------------------------
Title: Progress toward high resolution EUV spectroscopy
Authors: Korendyke, C.; Doschek, G. A.; Warren, H.; Young, P. R.;
Chua, D.; Hassler, D. M.; Landi, E.; Davila, J. M.; Klimchuck, J.;
Tun, S.; DeForest, C.; Mariska, J. T.; Solar C Spectroscopy Working
Group; LEMUR; EUVST Development Team
2013SPD....44..143K Altcode:
HIgh resolution EUV spectroscopy is a critical instrumental technique
to understand fundamental physical processes in the high temperature
solar atmosphere. Spectroscopic observations are used to measure
differential emission measure, line of sight and turbulent flows,
plasma densities and emission measures. Spatially resolved, spectra of
these emission lines with adequate cadence will provide the necessary
clues linking small scale structures with large scale, energetic
solar phenomena. The necessary observations to determine underlying
physical processes and to provide comprehensive temperature coverage
of the solar atmosphere above the chromosphere will be obtained by the
proposed EUVST instrument for Solar C. This instrument and its design
will be discussed in this paper. Progress on the VEry high Resolution
Imaging Spectrograph (VERIS) sounding rocket instrument presently under
development at the Naval Research Laboratory will also be discussed.
---------------------------------------------------------
Title: A Space Weather Mission to the Earth's 5th Lagrangian Point
(L5)
Authors: Howard, R. A.; Vourlidas, A.; Ko, Y.; Biesecker, D. A.;
Krucker, S.; Murphy, N.; Bogdan, T. J.; St Cyr, O. C.; Davila, J. M.;
Doschek, G. A.; Gopalswamy, N.; Korendyke, C. M.; Laming, J. M.;
Liewer, P. C.; Lin, R. P.; Plunkett, S. P.; Socker, D. G.; Tomczyk,
S.; Webb, D. F.
2012AGUFMSA13D..07H Altcode:
The highly successful STEREO mission, launched by NASA in 2006,
consisted of two spacecraft in heliocentric orbit, one leading and
one trailing the Earth and each separating from Earth at the rate
of about 22.5 degrees per year. Thus the two spacecraft have been
probing different probe/Sun/Earth angles. The utility of having remote
sensing and in-situ instrumentation away from the Sun-Earth line was
well demonstrated by STEREO. Here we propose the concept of a mission
at the 5th Lagrangian "point" in the Earth/Sun system, located behind
Earth about 60 degrees to the East of the Sun-Earth line. Such a mission
would enable many aspects affecting space weather to be well determined
and thus improving the prediction of the conditions of the solar wind
as it impinges on geospace. For example, Coronal Mass Ejections can
tracked for a significant distance toward Earth, new active regions
can be observed before they become visible to the Earth observer, the
solar wind can be measured before it rotates to Earth. The advantages
of such a mission will be discussed in this presentation.
---------------------------------------------------------
Title: Exploring Small Spatial Scales in the Transition Region
and Solar Corona with the Very High Angular Resolution Imaging
Spectrometer (VERIS)
Authors: Chua, D. H.; Korendyke, C. M.; Vourlidas, A.; Brown, C. M.;
Tun-Beltran, S.; Klimchuk, J. A.; Landi, E.; Seely, J.; Davila, J. M.;
Hagood, R.; Roberts, D.; Shepler, E.; Feldman, R.; Moser, J.; Shea, J.
2012AGUFMSH33A2217C Altcode:
Theoretical and experimental investigations of the transition region
and coronal loops point to the importance of processes occurring on
small spatial scales in governing the strong dynamics and impulsive
energy release in these regions. As a consequence, high spatial,
temporal, and temperature resolution over a broad temperature range,
and accuracy in velocity and density determinations are all critical
observational parameters. Current instruments lack one or more of these
properties. These observational deficiencies have created a wide array
of opposing descriptions of coronal loop heating and questions such
as whether or not the plasma within coronal loops is multi-thermal or
isothermal. High spectral and spatial resolution spectroscopic data
are absolutely required to resolve these controversies and to advance
our understanding of the dynamics within the solar atmosphere. We
will achieve this with the Very High Angular Resolution Imaging
Spectrometer (VERIS) sounding rocket payload. VERIS consists of an
off-axis paraboloid telescope feeding a very high angular resolution,
extreme ultraviolet (EUV) imaging spectrometer that will provide
the first ever, simultaneous sub-arcsecond (0.16 arcsecond/pixel)
spectra in bright lines needed to study plasma structures in the
transition region, quiet corona, and active region core. It will do
so with a spectral resolution of >5000 to allow Doppler velocity
determinations to better than 3 km/s. VERIS uses a novel two-element,
normal incidence optical design with highly reflective, broad wavelength
coverage EUV coatings to access a spectral range with broad temperature
coverage (0.03-15 MK) and density-sensitive line ratios. Combined with
Hinode Solar Optical Telescope (SOT) and ground based observatories,
VERIS will deliver simultaneous observations of the entire solar
atmosphere from the photosphere to the multi-million degree corona
at sub-arcsecond resolution for the first time ever, allowing us to
understand the missing link between chromospheric structures and the
corona. VERIS will be launched from White Sands Missile Range in early
2013. This paper presents a progress report on the VERIS payload and
a summary of observations planned to further our understanding of
the fine-scale structure of individual coronal loops and the heating
mechanisms operating within them.
---------------------------------------------------------
Title: LEMUR: Large European module for solar Ultraviolet
Research. European contribution to JAXA's Solar-C mission
Authors: Teriaca, Luca; Andretta, Vincenzo; Auchère, Frédéric;
Brown, Charles M.; Buchlin, Eric; Cauzzi, Gianna; Culhane, J. Len;
Curdt, Werner; Davila, Joseph M.; Del Zanna, Giulio; Doschek, George
A.; Fineschi, Silvano; Fludra, Andrzej; Gallagher, Peter T.; Green,
Lucie; Harra, Louise K.; Imada, Shinsuke; Innes, Davina; Kliem,
Bernhard; Korendyke, Clarence; Mariska, John T.; Martínez-Pillet,
Valentin; Parenti, Susanna; Patsourakos, Spiros; Peter, Hardi; Poletto,
Luca; Rutten, Robert J.; Schühle, Udo; Siemer, Martin; Shimizu,
Toshifumi; Socas-Navarro, Hector; Solanki, Sami K.; Spadaro, Daniele;
Trujillo-Bueno, Javier; Tsuneta, Saku; Dominguez, Santiago Vargas;
Vial, Jean-Claude; Walsh, Robert; Warren, Harry P.; Wiegelmann,
Thomas; Winter, Berend; Young, Peter
2012ExA....34..273T Altcode: 2011ExA...tmp..135T; 2011arXiv1109.4301T
The solar outer atmosphere is an extremely dynamic environment
characterized by the continuous interplay between the plasma and the
magnetic field that generates and permeates it. Such interactions play a
fundamental role in hugely diverse astrophysical systems, but occur at
scales that cannot be studied outside the solar system. Understanding
this complex system requires concerted, simultaneous solar observations
from the visible to the vacuum ultraviolet (VUV) and soft X-rays, at
high spatial resolution (between 0.1” and 0.3”), at high temporal
resolution (on the order of 10 s, i.e., the time scale of chromospheric
dynamics), with a wide temperature coverage (0.01 MK to 20 MK,
from the chromosphere to the flaring corona), and the capability of
measuring magnetic fields through spectropolarimetry at visible and
near-infrared wavelengths. Simultaneous spectroscopic measurements
sampling the entire temperature range are particularly important. These
requirements are fulfilled by the Japanese Solar-C mission (Plan B),
composed of a spacecraft in a geosynchronous orbit with a payload
providing a significant improvement of imaging and spectropolarimetric
capabilities in the UV, visible, and near-infrared with respect to
what is available today and foreseen in the near future. The Large
European Module for solar Ultraviolet Research (LEMUR), described
in this paper, is a large VUV telescope feeding a scientific payload
of high-resolution imaging spectrographs and cameras. LEMUR consists
of two major components: a VUV solar telescope with a 30 cm diameter
mirror and a focal length of 3.6 m, and a focal-plane package composed
of VUV spectrometers covering six carefully chosen wavelength ranges
between 170 Å and 1270 Å. The LEMUR slit covers 280” on the Sun with
0.14” per pixel sampling. In addition, LEMUR is capable of measuring
mass flows velocities (line shifts) down to 2 km s<SUP> - 1</SUP> or
better. LEMUR has been proposed to ESA as the European contribution
to the Solar C mission.
---------------------------------------------------------
Title: Observations from the HRTS-9 Rocket in the NUV Passband of
the IRIS Mission
Authors: Korendyke, C.; Morrill, J. S.; Floyd, L. E.; McMullin, D. R.
2011AGUFMSH13B1961K Altcode:
The HRTS-9 rocket flew in April 1995 and observed a variety of solar
surface features on the western portion of the solar disk. Unlike
previous flights, the spectrograph was modified to observe a roughly
180 A wide portion the NUV solar spectrum near the Mg II doublet at
2800 A. In addition, a slit-jaw camera observed a 400 x 900 arcsecond
region around the 960 arcsecond long (1 Rsun) x 1 arcsecond wide
spectrograph slit in four UV passbands. Specifically, a series of
narrowband images were measured at 1540 A (Si I), 1550 A ( C IV), 1560
A ( C I), and 1600 A (continuum). Images of H-alpha were measured as
well. During the flight, the spectrograph slit was pointed at various
features including the quiet sun near disk center and the limb, several
active regions, and a sunspot. During the final portion of the flight,
the rocket pointing was fixed and a slit scanning mechanism was used
to collect a series of spectra that span about 45 arcseconds. From
this data set spectral images at specific wavelengths in the 2765 to
2885 A range can be generated and compared to the broadband images at
shorter wavelengths. For example, preliminary spectral images in the
Mg II k line show evidence of loop structures similar to those seen in
C IV. Our previous efforts with this data set has focused on the impact
these radiance observations near Mg II have on solar spectral irradiance
studies. These topics include examining the sources of solar irradiance
variability, the center-to-limb variability of the quiet sun, and the
relationship between the Mg II intensity and the photospheric magnetic
field. In light of the upcomming IRIS Explorer mission, we are turning
our attention to those science goals in order to anticipate and support
potential observations by the IRIS NUV spectrograph channel. In this
presentation we will present an overview of the available observations
and previous results as well as discuss our ongoing analysis and
preliminary spectral images of features in the region near Mg II.
---------------------------------------------------------
Title: Observations of the White Light Corona from Solar Orbiter
and Solar Probe Plus
Authors: Howard, R. A.; Thernisien, A. F.; Vourlidas, A.; Plunkett,
S. P.; Korendyke, C. M.; Sheeley, N. R.; Morrill, J. S.; Socker,
D. G.; Linton, M. G.; Liewer, P. C.; De Jong, E. M.; Velli, M. M.;
Mikic, Z.; Bothmer, V.; Lamy, P. L.
2011AGUFMSH43F..06H Altcode:
The SoloHI instrument on Solar Orbiter and the WISPR instrument on Solar
Probe+ will make white light coronagraphic images of the corona as the
two spacecraft orbit the Sun. The minimum perihelia for Solar Orbiter
is about 60 Rsun and for SP+ is 9.5 Rsun. The wide field of view of the
WISPR instrument (about 105 degrees radially) corresponds to viewing
the corona from 2.2 Rsun to 20 Rsun. Thus the entire Thomson hemisphere
is contained within the telescope's field and we need to think of
the instrument as being a traditional remote sensing instrument and
then transitioning to a local in-situ instrument. The local behavior
derives from the fact that the maximum Thomson scattering will favor
the electron plasma close to the spacecraft - exactly what the in-situ
instruments will be sampling. SoloHI and WISPR will also observe
scattered light from dust in the inner heliosphere, which will be an
entirely new spatial regime for dust observations from a coronagraph,
which we assume to arise from dust in the general neighborhood of about
half way between the observer and the Sun. As the dust grains approach
the Sun, they evaporate and do not contribute to the scattering. A
dust free zone has been postulated to exist somewhere inside of 5 Rsun
where all dust is evaporated, but this has never been observed. The
radial position where the evaporation occurs will depend on the
precise molecular composition of the individual grains. The orbital
plane of Solar Orbiter will gradually increase up to about 35 degrees,
enabling a very different view through the zodiacal dust cloud to test
the models generated from in-ecliptic observations. In this paper we
will explore some of the issues associated with the observation of
the dust and will present a simple model to explore the sensitivity
of the instrument to observe such evaporations.
---------------------------------------------------------
Title: LEMUR (Large European Module for solar Ultraviolet Research):
a VUV imaging spectrograph for the JAXA Solar-C Mission
Authors: Korendyke, Clarence M.; Teriaca, Luca; Doschek, George A.;
Harra, Louise K.; Schühle, Udo H.; Shimizu, Toshifumi
2011SPIE.8148E..0IK Altcode: 2011SPIE.8148E..17K
LEMUR is a VUV imaging spectrograph with 0.28" resolution. Incident
solar radiation is imaged onto the spectrograph slit by a single
mirror telescope consisting of a 30-cm steerable f/12 off-axis
paraboloid mirror. The spectrograph slit is imaged and dispersed by
a highly corrected grating that focuses the solar spectrum over the
detectors. The mirror is coated with a suitable multilayer with B4C
top-coating providing a reflectance peak around 18.5 nm besides the
usual B4C range above 500Å. The grating is formed by two halves, one
optimized for performances around 185Å and the other above 500Å. Three
intensified CCD cameras will record spectra above 50 nm while a large
format CCD array with an aluminum filter will be used around 185Å.
---------------------------------------------------------
Title: Earth-Affecting Solar Causes Observatory (EASCO): a mission
at the Sun-Earth L5
Authors: Gopalswamy, Nat; Davila, Joseph M.; Auchère, Frédéric;
Schou, Jesper; Korendyke, Clarence M.; Shih, Albert; Johnston, Janet
C.; MacDowall, Robert J.; Maksimovic, Milan; Sittler, Edward; Szabo,
Adam; Wesenberg, Richard; Vennerstrom, Suzanne; Heber, Bernd
2011SPIE.8148E..0ZG Altcode: 2011SPIE.8148E..30G; 2011arXiv1109.2929G
Coronal mass ejections (CMEs) and corotating interaction regions
(CIRs) as well as their source regions are important because of
their space weather consequences. The current understanding of CMEs
primarily comes from the Solar and Heliospheric Observatory (SOHO)
and the Solar Terrestrial Relations Observatory (STEREO) missions,
but these missions lacked some key measurements: STEREO did not have a
magnetograph; SOHO did not have in-situ magnetometer. SOHO and other
imagers such as the Solar Mass Ejection Imager (SMEI) located on the
Sun-Earth line are also not well-suited to measure Earth-directed
CMEs. The Earth-Affecting Solar Causes Observatory (EASCO) is a
proposed mission to be located at the Sun-Earth L5 that overcomes
these deficiencies. The mission concept was recently studied at the
Mission Design Laboratory (MDL), NASA Goddard Space Flight Center,
to see how the mission can be implemented. The study found that the
scientific payload (seven remote-sensing and three in-situ instruments)
can be readily accommodated and can be launched using an intermediate
size vehicle; a hybrid propulsion system consisting of a Xenon ion
thruster and hydrazine has been found to be adequate to place the
payload at L5. Following a 2-year transfer time, a 4-year operation
is considered around the next solar maximum in 2025.
---------------------------------------------------------
Title: The coronal suprathermal particle explorer (C-SPEX)
Authors: Moses, J. Daniel; Brown, Charles; Doschek, George; Ko,
Yuan-Kuen; Korendyke, Clarence; Laming, J. Martin; Socker, Dennis;
Tylka, Allen; McMullin, Donald; Ng, Chee; Wassom, Steven; Lee, Martin;
Auchère, Frédéric; Fineschi, Silvano; Carter, Tim
2011SPIE.8148E..0JM Altcode: 2011SPIE.8148E..18M
The primary science objective of the Coronal Suprathermal Particle
Explorer (C-SPEX) is to investigate the spatial and temporal
variations of coronal suprathermal particle populations that are
seeds for acceleration to solar energetic particles (SEPs). It is
understood that such seed particle populations vary with coronal
structures and can change responding to solar flare and coronal mass
ejection (CME) events. Models have shown that higher densities of
suprathermal protons can result in higher rates of acceleration to
high energies. Understanding the variations in the suprathermal seed
particle population is thus crucial for understanding the variations
in SEPs. However, direct measurements are still lacking. C-SPEX
will measure the variation in the suprathermal protons across
various coronal magnetic structures, before/after the passage of CME
shocks, in the post-CME current sheets, and before/after major solar
flares. Understanding the causes for variation in the suprathermal
seed particle population and its effect on the variation in SEPs
will also help build the predictive capability of SEPs that reach
Earth. The CSPEX measurements will be obtained from instrumentation
on the International Space Station (ISS) employing well-established
UV coronal spectroscopy techniques.
---------------------------------------------------------
Title: Straylight-Rejection Performance of the STEREO HI Instruments
Authors: Halain, J. -P.; Eyles, C. J.; Mazzoli, A.; Bewsher, D.;
Davies, J. A.; Mazy, E.; Rochus, P.; Defise, J. M.; Davis, C. J.;
Harrison, R. A.; Crothers, S. R.; Brown, D. S.; Korendyke, C.; Moses,
J. D.; Socker, D. G.; Howard, R. A.; Newmark, J. S.
2011SoPh..271..197H Altcode: 2011SoPh..tmp..189H; 2011SoPh..tmp..132H; 2011SoPh..tmp..258H
The SECCHI Heliospheric Imager (HI) instruments on-board the STEREO
spacecraft have been collecting images of solar wind transients,
including coronal mass ejections, as they propagate through the inner
heliosphere since the beginning of 2007.
---------------------------------------------------------
Title: Observations From The Hrts-9 Rocket In The Nuv Passband Of
The Iris Mission
Authors: Morrill, Jeff S.; Korendyke, C.; McMullin, D.; Floyd, L.
2011SPD....42.1730M Altcode: 2011BAAS..43S.1730M
The HRTS-9 rocket flew in April 1995 and observed several solar
surface features on the western solar disk. The HRTS-9 spectrograph
was modified to observe a 180 A wide portion of the solar spectrum near
MgII at 2800 A. Also, a slit-jaw camera observed a 400" x 900" region
around the 960" long x 1" wide spectrograph slit in five passbands,
specifically, 1540A (Si I), 1550A (C IV), 1560A (C I), 1600A, and
images of H-alpha. <P />During the flight, the slit was pointed at
various features including the quiet sun near disk center and the limb,
active regions, and a sunspot. At the end of the flight, the pointing
was fixed and a slit scanning mechanism was used to collect a series
of spectra that span about 45". From this data set spectral images at
specific wavelengths in the 2765 to 2885A range can be generated and
compared to the broadband images at shorter wavelengths. For example,
preliminary spectral images in the MgII k line show evidence of loop
structures similar to those seen in C IV. Our previous efforts with
this data set have focused on the impact these radiance observations
near MgII have on solar spectral irradiance studies. These topics
include examining the sources of solar irradiance variability, the
center-to-limb variability of the quiet sun, and the relationship
between the MgII intensity and the photospheric magnetic field. In light
of the upcoming IRIS Explorer mission, we are turning our attention
to those science goals in order to anticipate and support potential
observations by the IRIS NUV spectrograph channel. <P />In this
presentation we describe the available observations, previous results,
as well as discuss our ongoing analysis and preliminary spectral images
of features in the region near MgII. Work was sponsored by NASA.
---------------------------------------------------------
Title: The Coronal Suprathermal Particle Explorer (C-SPEX)
Authors: Moses, John Daniel; Brown, C. M.; Doschek, G. A.; -. Ko,
Y.; Korendyke, C. M.; Laming, J. M.; Rakowski, C. E.; Socker, D. G.;
Tylka, A.; Ng, C. K.; Wassom, S. R.; McMullin, D. R.; Lee, M. A.;
Auchere, F.; Fineschi, S.
2011SPD....42.1519M Altcode: 2011BAAS..43S.1519M
The primary science objective of the Coronal Suprathermal Particle
Explorer (C-SPEX) is to investigate the spatial and temporal
variations of coronal suprathermal particle populations that are
seeds for acceleration to solar energetic particles (SEPs). It is
understood that such seed particle populations vary with coronal
structures and can change responding to solar flare and coronal mass
ejection (CME) events. Models have shown that higher densities of
suprathermal protons can result in higher rates of acceleration to
high energies. Understanding the variations in the suprathermal seed
particle population is thus crucial for understanding the variations
in SEPs. However, direct measurements are still lacking. <P />C-SPEX
will measure the variation in the suprathermal protons across various
coronal magnetic structures, before/after the passage of CME shocks, in
the post-CME current sheets, and before/after major solar flares. The
measurements will not only constrain models of SEP acceleration but
also constrain models of the production of suprathermal particles from
processes such as magnetic reconnection at the Sun. Understanding the
causes for variation in the suprathermal seed particle population and
its effect on the variation in SEPs will also help build the predictive
capability of SEPs that reach Earth. <P />The C-SPEX measurements will
be obtained from instrumentation on the International Space Station
(ISS) employing well-established UV coronal spectroscopy techniques. The
unique aspect of C-SPEX is a >100-fold increase of light gathering
power over any previous UV coronal spectrometer. It is demonstrated
C-SPEX will thus overcome the limitations in signal to noise that have
thwarted prior attempts to observe suprathermals in the corona. <P />The
present lack of a means to predict the variability of SEP intensities
and the likelihood C-SPEX will help develop such predictions makes the
proposed investigation directly relevant to each of the three strategic
objectives of the NASA Heliophysics Research Strategic Objectives.
---------------------------------------------------------
Title: The Wide Field Imager for Solar PRobe (WISPR)
Authors: Plunkett, S. P.; Howard, R. A.; Vourlidas, A.; Korendyke,
C. M.; Socker, D. G.; Morrill, J. S.; Sheeley, N. R.; Linton, M.;
Liewer, P. C.; de Jong, E. M.; Mikic, Z.
2010AGUFMSH11B1622P Altcode:
The Wide Field Imager for Solar PRobe (WISPR) will image the
Thomson-scattered light from the coronal plasma in the inner corona,
with unprecedented spatial resolution, cadence, and sensitivity. WISPR
follows on the SECCHI Heliospheric Imager (HI) aboard the STEREO
mission, and addresses all four key objectives in the Solar Probe Plus:
Report of the STDT (2008): (1) Determine the structure and dynamics of
the magnetic fields at the sources of the fast and slow solar wind, (2)
Trace the flow of energy that heats the solar corona and accelerates
the SW, (3) explore the mechanisms that accelerate and transport
energetic particles, (4) explore dusty plasma phenomena and their
influence on the solar wind and energetic particle formation. Situated
in the ram direction of the Solar Probe Plus (SPP) spacecraft (S/C),
WISPR will have the unique ability to image the coronal structures when
they are close to the Sun, as they approach, and as they pass over the
spacecraft. As a remote sensor, WISPR will connect the structures close
to the Sun to the spacecraft and provide important spatial and temporal
information; measuring, for example, the properties of the structures
generating the shocks and SEPs that will be measured in a few minutes at
the S/C. Since the S/C is embedded in the corona, WISPR and the in situ
instruments will measure for the first time the same plasma. Also as
the SPP transits through the corona, the rapidly-varying viewpoint and
high spatial resolution of WISPR will enable tomographic imaging of the
corona, and lead to higher fidelity and finer scale 3D reconstructions
than are possible with the STEREO mission or single-view rotational
tomography. The wide field of view will include at times other inner
heliospheric probes (e.g. Solar Orbiter) and will image the outflowing
wind that is impinging on that probe. In addition to this standard
imaging mode, WISPR opens a new capability for imaging instruments,
the measurement of pressure turbulence by employing a high cadence mode
(~1 sec) to image a small region in the corona. For the first time,
the slopes of the power spectral density from images can be compared
directly to the density and magnetic field fluctuations seen in situ as
a function of coronal spatial structure and heliocentric distance. In
addition, the 1 sec cadence can be generated anywhere within the WISPR
field, enabling the study of the transition of the solar wind injected
at the tops of the helmet streamers to inertial dissipation scales.
---------------------------------------------------------
Title: Imaging the Solar Wind with SoloHI
Authors: Howard, R. A.; Vourlidas, A.; Plunkett, S. P.; Korendyke,
C. M.; McMullin, D. R.; Liewer, P. C.; Velli, M. M.; Solohi
2010AGUFMSH11B1627H Altcode:
Imaging outflows in the corona have been observed with the SOHO/LASCO
instrument, since 1996. With the launch of the STEREO mission in
2006, these outflows can be followed into the heliosphere, with the
SECCHI/Heliospheric Imager. For the Solar Orbiter mission, we have
proposed an instrument called the Solar Orbiter Heliospheric Imager
(SoloHI) to be able to image the solar wind and the density fluctuations
in the wind and thus provide the link between the in-situ and remote
sensing measurements. The nature of the Thomson scattering process
integrates along a particular look direction but the scattering is a
maximum on the Thomson sphere - the locus of points that form a right
angle between the look direction and the solar vector. The experience
from SECCHI/HI shows that the density fluctuations are easily visible
and can be tracked back into the low corona, enabling a coupling
between the solar wind plasma crossing the spacecraft and the source
region in the corona. However, the SECCHI/HI observations have low
cadence and long integration times. As a new observing mode for SoloHI,
we have implemented a capability to readout a subset of the image at
a time cadence of about 1 second. Thus small scale fluctuations can
be observed in addition to the large scale fluctuations observed from
SECCHI/HI. This will enable us to determine the spectral index of the
density fluctuations over an unprecedented range of heights (from 5 to
135 Rsun) to compare with the in-situ determinations of the spectral
index. This may indicate whether the fluctuations are generated close
to the sun and convected out by the solar wind or are generated within
the solar wind.
---------------------------------------------------------
Title: The Structure and Dynamics of the Upper Chromosphere and Lower
Transition Region as Revealed by the Subarcsecond VAULT Observations
Authors: Vourlidas, A.; Sanchez Andrade-Nuño, B.; Landi, E.;
Patsourakos, S.; Teriaca, L.; Schühle, U.; Korendyke, C. M.;
Nestoras, I.
2010SoPh..261...53V Altcode: 2009arXiv0912.2272V
The Very high Angular resolution ULtraviolet Telescope (VAULT) is a
sounding rocket payload built to study the crucial interface between
the solar chromosphere and the corona by observing the strongest line
in the solar spectrum, the Ly α line at 1216 Å. In two flights, VAULT
succeeded in obtaining the first ever subarcsecond ( 0.5\hbox{$^”$}
) images of this region with high sensitivity and cadence. Detailed
analyses of those observations contributed significantly to new
ideas about the nature of the transition region. Here, we present
a broad overview of the Ly α atmosphere as revealed by the VAULT
observations and bring together past results and new analyses from the
second VAULT flight to create a synthesis of our current knowledge
of the high-resolution Ly α Sun. We hope that this work will serve
as a good reference for the design of upcoming Ly α telescopes and
observing plans.
---------------------------------------------------------
Title: Irradiance Calibration Using a Cryogenic Radiometer and a
Broadband Light Source
Authors: Morrill, J. S.; McMullin, D.; Floyd, L. E.; Lorentz, S. R.;
Korendyke, C. M.
2009AGUFMSH13C..07M Altcode:
Total solar irradiance measurements have been made from space based
instruments for the past several decades. Due to a variety of reasons
which range from instrumental degradation to differences in optical
design, the data from these sources have proved difficult to overlap
and place on an absolute scale. Some previous calibration efforts have
used the sun as a source while operating the instrument in a large
vacuum chamber. More recent efforts to provide ground based, pre-flight
intercomparisons between flight radiometers and recently developed high
power cryogenic radiometers using lasers. We are currently developing
a calibration facility at The Naval Research Laboratory which uses
a high power cryogenic radiometer with a broadband light source with
near solar illumination. The system uses a very low scattered light
vacuum calibration tank used to perform the stray light tests of the
LASCO and SECCHI coronagraphs on the SOHO and STEREO missions. This
presentation will address the status of our system, recent measurements,
and future plans.
---------------------------------------------------------
Title: The Sub-arcsecond Structure Of The Upper Chromosphere:
Results From The 2nd Flight Of The Nrl Vault Sounding Rocket Payload
Authors: Sanchez-Andrade Nuno, Bruno; Vourlidas, A.; Korendyke, C.
2009SPD....40.2901S Altcode:
The Very high Angular resolution ULtraviolet Telescope (VAULT) is an Lya
spectroheliograph flown on a sounding rocket. The payload is capable of
obtaining Lya filtergrams with a spatial resolution of around 0.33” (
200 km) over an extended field of view (535” x 235”) . The instrument
is tuned to the Ly-a line because it forms at the boundary of the upper
chromosphere low corona. On its last flight, on 14 June 2002, VAULT
observed an area around NOAA AR 9997 & 9998 with a rich variety
of features: quiet Sun network, limb spicules, filaments, prominences
and plage. <P />The observing campaign incorporated a wide variety of
ground-based and space-borne instruments. The level 0.9 VAULT data is
open and available from http://wwwsolar.nrl.navy.mil/rockets/vault .We
have recently releseased SolarSoft-compatible software for easy access
and processing of the data. <P />This contribution showcases the data
capabilities and availability. We present contrast-enhanced images by
means of wavelet image processing. The images reveal in extraordinary
detail the dynamics of the smallest solar scales (200-300 km). We
observe flows along thin threads on the prominence, exploding events
on the plage and even in the quiet sun regions.
---------------------------------------------------------
Title: High-Resolution Center-to-Limb Variation of the Quiet Solar
Spectrum near Mg II
Authors: Morrill, J. S.; Korendyke, C. M.
2008ApJ...687..646M Altcode:
The accurate determination of the center-to-limb variation of the quiet
solar spectrum is of fundamental importance to our understanding of
both spatially resolved solar spectral radiance as well as full-disk
spectral irradiance. Previous studies have examined the center-to-limb
variation at various spectral resolutions using both observations and
calculations. Here we derive the center-to-limb variation near Mg II
at 2800 Å from observations made by the HRTS-9 rocket-spectrograph
at both high spatial (1”) and spectral (0.2 Å) resolution. This
region of the solar spectrum is important because of its impact on the
terrestrial atmosphere and its use in generating the Mg II index. The
initial part of this paper presents the correction methods used to
determine the center-to-limb variation, including the determination
of the vignetting properties of the HRTS-9 instrument. This latter
correction accounts for the intensity variation along the slit axis
of the observed spectrogram. The resulting center-to-limb variation
is employed in a model of solar spectral irradiance near Mg II. Using
these results and calibrated solar spectra, the absolute intensity
calibration is determined for the HRTS-9 spectra. An important aspect
of the high-resolution center-to-limb variation is the presence of many
spectral features illustrating the differences between the wings and
cores of the numerous Fraunhofer lines in the 2765-2875 Å region. Also,
both the Mg I and Mg II lines in this spectral region have broad,
smooth wings that vary differently than the nearby line-blanketed
continuum. The results of this study will provide a good source of
comparison for detailed models of the quiet solar spectrum.
---------------------------------------------------------
Title: Janus: Observing the Sun-Earth Connection. A Lunar Mission
Design Study
Authors: Herman, J. R.; Davilla, J.; Korendyke, C.; Hamill, P.
2008LPICo1415.2004H Altcode:
The Moon is a stable platform for obtaining simultaneous views of
the Earth and Sun by the deployment of two proven instrument packages
(Janus) on the moon's surface to understand the coupling between the
Sun and Earth.
---------------------------------------------------------
Title: Wavelengths and Intensities of Spectral Lines in the 171-211
and 245-291 Å Ranges from Five Solar Regions Recorded by the
Extreme-Ultraviolet Imaging Spectrometer (EIS) on Hinode
Authors: Brown, C. M.; Feldman, U.; Seely, J. F.; Korendyke, C. M.;
Hara, H.
2008ApJS..176..511B Altcode:
We present spectral line wavelengths, identifications, and intensities
in the 171-211 and 245-291 Å ranges from five solar plasma regions
recorded by the Extreme-Ultraviolet Imaging Spectrometer (EIS)
on Hinode. The recorded data were emitted from a quiet region,
two active areas on the solar disk, a limb region, and a region
20” above the limb. The line list contains 500 lines of which 55%
were identified with previously known transitions. Although the EIS
spectral coverage is limited to two ranges approximately 40 Å wide,
the identified lines belong to a total of 56 ions from 15 elements.
---------------------------------------------------------
Title: High Resolution Center-To-Limb Variation of the Quiet Solar
Spectrum Near Mg II
Authors: Morrill, J. S.; Korendyke, C. M.
2008AGUSMSP21B..02M Altcode:
The accurate determination of the high resolution center to limb
variation of the solar spectrum is of fundamental importance to our
understanding of both spatially resolved solar spectral radiance as
well as full disk spectral irradiance. Previous studies have examined
the center to limb variation at various spectral resolutions using both
observations and calculations. In his study we derive the center to
limb variation near Mg II at 2800 A from observations made by the HRTS
rocket spectrograph at both high spatial (1-arc second) and spectral
(0.077A) resolution. We present the details of the methods used in this
derivation including the determination of the vignetting properties of
the HRTS instrument. This latter correction accounts for the intensity
variation along the slit axis of the observed spectrogram. The resulting
center to limb variation is use in a model of solar spectral irradiance
near Mg II. Using these results and calibrated solar irradiance spectra
the absolute intensity calibration is generated for the HRTS spectra. An
important aspect of the high resolution center to limb variation we
present is the presence of many spectral features demonstrating the
differences between the wings and cores of the numerous Fraunhofer
lines in the 2765-2875 A region. In addition, both the Mg I and Mg
II lines in this spectral region have very broad smooth wings with
significant variation across these spectral features. The results
of this study will provide a good source of comparison for detailed
models of the solar spectrum.
---------------------------------------------------------
Title: Sun Earth Connection Coronal and Heliospheric Investigation
(SECCHI)
Authors: Howard, R. A.; Moses, J. D.; Vourlidas, A.; Newmark, J. S.;
Socker, D. G.; Plunkett, S. P.; Korendyke, C. M.; Cook, J. W.; Hurley,
A.; Davila, J. M.; Thompson, W. T.; St Cyr, O. C.; Mentzell, E.;
Mehalick, K.; Lemen, J. R.; Wuelser, J. P.; Duncan, D. W.; Tarbell,
T. D.; Wolfson, C. J.; Moore, A.; Harrison, R. A.; Waltham, N. R.;
Lang, J.; Davis, C. J.; Eyles, C. J.; Mapson-Menard, H.; Simnett,
G. M.; Halain, J. P.; Defise, J. M.; Mazy, E.; Rochus, P.; Mercier,
R.; Ravet, M. F.; Delmotte, F.; Auchere, F.; Delaboudiniere, J. P.;
Bothmer, V.; Deutsch, W.; Wang, D.; Rich, N.; Cooper, S.; Stephens,
V.; Maahs, G.; Baugh, R.; McMullin, D.; Carter, T.
2008SSRv..136...67H Altcode: 2008SSRv..tmp...64H
The Sun Earth Connection Coronal and Heliospheric Investigation
(SECCHI) is a five telescope package, which has been developed for
the Solar Terrestrial Relation Observatory (STEREO) mission by the
Naval Research Laboratory (USA), the Lockheed Solar and Astrophysics
Laboratory (USA), the Goddard Space Flight Center (USA), the University
of Birmingham (UK), the Rutherford Appleton Laboratory (UK), the
Max Planck Institute for Solar System Research (Germany), the Centre
Spatiale de Leige (Belgium), the Institut d’Optique (France) and the
Institut d’Astrophysique Spatiale (France). SECCHI comprises five
telescopes, which together image the solar corona from the solar disk to
beyond 1 AU. These telescopes are: an extreme ultraviolet imager (EUVI:
1 1.7 R<SUB>⊙</SUB>), two traditional Lyot coronagraphs (COR1: 1.5 4
R<SUB>⊙</SUB> and COR2: 2.5 15 R<SUB>⊙</SUB>) and two new designs
of heliospheric imagers (HI-1: 15 84 R<SUB>⊙</SUB> and HI-2: 66 318
R<SUB>⊙</SUB>). All the instruments use 2048×2048 pixel CCD arrays
in a backside-in mode. The EUVI backside surface has been specially
processed for EUV sensitivity, while the others have an anti-reflection
coating applied. A multi-tasking operating system, running on a PowerPC
CPU, receives commands from the spacecraft, controls the instrument
operations, acquires the images and compresses them for downlink
through the main science channel (at compression factors typically
up to 20×) and also through a low bandwidth channel to be used for
space weather forecasting (at compression factors up to 200×). An
image compression factor of about 10× enable the collection of images
at the rate of about one every 2 3 minutes. Identical instruments,
except for different sizes of occulters, are included on the STEREO-A
and STEREO-B spacecraft.
---------------------------------------------------------
Title: Heliospheric Images of the Solar Wind at Earth
Authors: Sheeley, N. R., Jr.; Herbst, A. D.; Palatchi, C. A.; Wang,
Y. -M.; Howard, R. A.; Moses, J. D.; Vourlidas, A.; Newmark, J. S.;
Socker, D. G.; Plunkett, S. P.; Korendyke, C. M.; Burlaga, L. F.;
Davila, J. M.; Thompson, W. T.; St. Cyr, O. C.; Harrison, R. A.;
Davis, C. J.; Eyles, C. J.; Halain, J. P.; Wang, D.; Rich, N. B.;
Battams, K.; Esfandiari, E.; Stenborg, G.
2008ApJ...675..853S Altcode:
During relatively quiet solar conditions throughout the spring and
summer of 2007, the SECCHI HI2 white-light telescope on the STEREO
B solar-orbiting spacecraft observed a succession of wave fronts
sweeping past Earth. We have compared these heliospheric images with
in situ plasma and magnetic field measurements obtained by near-Earth
spacecraft, and we have found a near perfect association between the
occurrence of these waves and the arrival of density enhancements
at the leading edges of high-speed solar wind streams. Virtually
all of the strong corotating interaction regions are accompanied by
large-scale waves, and the low-density regions between them lack such
waves. Because the Sun was dominated by long-lived coronal holes and
recurrent solar wind streams during this interval, there is little
doubt that we have been observing the compression regions that are
formed at low latitude as solar rotation causes the high-speed wind
from coronal holes to run into lower speed wind ahead of it.
---------------------------------------------------------
Title: SECCHI Observations of the Sun's Garden-Hose Density Spiral
Authors: Sheeley, N. R., Jr.; Herbst, A. D.; Palatchi, C. A.; Wang,
Y. -M.; Howard, R. A.; Moses, J. D.; Vourlidas, A.; Newmark, J. S.;
Socker, D. G.; Plunkett, S. P.; Korendyke, C. M.; Burlaga, L. F.;
Davila, J. M.; Thompson, W. T.; St. Cyr, O. C.; Harrison, R. A.;
Davis, C. J.; Eyles, C. J.; Halain, J. P.; Wang, D.; Rich, N. B.;
Battams, K.; Esfandiari, E.; Stenborg, G.
2008ApJ...674L.109S Altcode:
The SECCHI HI2 white-light imagers on the STEREO A and B spacecraft
show systematically different proper motions of material moving outward
from the Sun in front of high-speed solar wind streams from coronal
holes. As a group of ejections enters the eastern (A) field of view,
the elements at the rear of the group appear to overrun the elements
at the front. (This is a projection effect and does not mean that the
different elements actually merge.) The opposite is true in the western
(B) field; the elements at the front of the group appear to run away
from the elements at the rear. Elongation/time maps show this effect
as a characteristic grouping of the tracks of motion into convergent
patterns in the east and divergent patterns in the west, consistent
with ejections from a single longitude on the rotating Sun. Evidently,
we are observing segments of the "garden-hose" spiral made visible
when fast wind from a low-latitude coronal hole compresses blobs of
streamer material being shed at the leading edge of the hole.
---------------------------------------------------------
Title: Coronal Dimming Observed with Hinode: Outflows Related to a
Coronal Mass Ejection
Authors: Harra, Louise K.; Hara, Hirohisa; Imada, Shinsuke; Young,
Peter R.; Williams, David R.; Sterling, Alphonse C.; Korendyke,
Clarence; Attrill, Gemma D. R.
2007PASJ...59S.801H Altcode:
Coronal dimming has been a signature used to determine the source
of plasma that forms part of a coronal mass ejection (CME) for many
years. Generally dimming is detected through imaging instruments such
as SOHO EIT by taking difference images. Hinode tracked active region
10930 from which there were a series of flares. We combined dimming
observations from EIT with Hinode data to show the impact of flares
and coronal mass ejections on the region surrounding the flaring
active region, and we discuss evidence that the eruption resulted in
a prolonged steady outflow of material from the corona. The dimming
region shows clear structure with extended loops whose footpoints are
the source of the strongest outflow (≈ 40 kms<SUP>-1</SUP>). This
confirms that the loops that are disrupted during the event do lose
plasma and hence are likely to form part of the CME. This is the
first time the velocity of the coronal plasma has been measured in an
extended dimming region away from the flare core. In addition there
was a weaker steady outflow from extended, faint loops outside the
active region before the eruption, which is also long lasting. These
were disturbed and the velocity increased following the flare. Such
outflows could be the source of the slow solar wind.
---------------------------------------------------------
Title: Wavelength Determination for Solar Features Observed by the
EUV Imaging Spectrometer on Hinode
Authors: Brown, Charles M.; Hara, Hirohisa; Kamio, Suguru; Feldman,
Uri; Seely, John F.; Doschek, George A.; Mariska, John T.; Korendyke,
Clarence M.; Lang, James; Dere, Kenneth P.; Culhane, Len; Thomas,
Roger J.; Davila, Joseph M.
2007PASJ...59S.865B Altcode:
A wavelength calibration of solar lines observed by the high
resolution EUV Imaging Spectrometer (EIS) on the Hinode satellite
is reported. Spectral features of the quiet sun and of two mildly
active areas were measured and calibrated. A listing of the stronger
observed lines with identification of the leading contributor ions
is presented. 41 lines are reported, with 90% identified. Wavelength
precisions (2σ) of ±0.0031Å for the EIS short band and ±0.0029Å
for the EIS long band are obtained. These lines, typical of 1-2
×10<SUP>6</SUP> K plasmas, are recommended as standards for the
establishment of EIS wavelength scales. The temperature of EIS varies
by about 1D.5 C around the orbit and also with spacecraft pointing. The
correlation of these temperature changes with wavelength versus pixel
number scale changes is reported.
---------------------------------------------------------
Title: Progress Toward A Very High Angular Resolution Imaging
Spectrometer (VERIS)
Authors: Korendyke, Clarence M.; Vourlidas, A.; Landi, E.; Seely,
J.; Klimchuck, J.
2007AAS...210.2604K Altcode: 2007BAAS...39Q.324K
Recent imaging at arcsecond (TRACE) and sub-arcsecond (VAULT) spatial
resolution clearly show that structures with fine spatial scales
play a key role in the physics of the upper solar atmosphere. Both
theoretical and observational considerations point to the importance
of small spatial scales, impulsive energy release, strong dynamics,
and extreme plasma nonuniformity. Fundamental questions regarding the
nature, structure, properties and dynamics of loops and filamentary
structures in the upper atmosphere have been raised. <P />To address
these questions, we are developing a next generation, VEry high
angular Resolution Imaging Spectrometer (VERIS) as a sounding rocket
instrument. VERIS will obtain the necessary high spatial resolution,
high fidelity measurements of plasma temperatures, densities and
velocities. With broad simultaneous temperature coverage, the VERIS
observations will directly address unresolved issues relating to
interconnections of various temperature solar plasmas. VERIS will
provide the first ever subarcsecond spectra of transition region and
coronal structures. It will do so with a sufficient spectral resolution
of to allow centroided Doppler velocity determinations to better than 3
km/s. VERIS uses a novel two element, normal incidence optical design
with highly reflective EUV coatings to access a spectral range with
broad temperature coverage (0.03-15 MK) and density-sensitive line
ratios. Finally, in addition to the spectra, VERIS will simultaneously
obtain spectrally pure slot images (10x150 arcsec) in the +/-1 grating
orders, which can be combined to make instantaneous line-of-sight
velocity maps with 8km/s accuracy over an unprecedented field of
view. <P />The VERIS program is beginning the second year of its
three year development cycle. All design activities and reviews are
complete. Fabrication of all major components has begun. Brassboard
electronics cards have been fabricated, assembled and tested. The paper
presents the essential scientific characteristics of the instrument.
---------------------------------------------------------
Title: The EUV Imaging Spectrometer for Hinode
Authors: Culhane, J. L.; Harra, L. K.; James, A. M.; Al-Janabi, K.;
Bradley, L. J.; Chaudry, R. A.; Rees, K.; Tandy, J. A.; Thomas, P.;
Whillock, M. C. R.; Winter, B.; Doschek, G. A.; Korendyke, C. M.;
Brown, C. M.; Myers, S.; Mariska, J.; Seely, J.; Lang, J.; Kent,
B. J.; Shaughnessy, B. M.; Young, P. R.; Simnett, G. M.; Castelli,
C. M.; Mahmoud, S.; Mapson-Menard, H.; Probyn, B. J.; Thomas, R. J.;
Davila, J.; Dere, K.; Windt, D.; Shea, J.; Hagood, R.; Moye, R.; Hara,
H.; Watanabe, T.; Matsuzaki, K.; Kosugi, T.; Hansteen, V.; Wikstol, Ø.
2007SoPh..243...19C Altcode:
The EUV Imaging Spectrometer (EIS) on Hinode will observe solar corona
and upper transition region emission lines in the wavelength ranges
170 - 210 Å and 250 - 290 Å. The line centroid positions and profile
widths will allow plasma velocities and turbulent or non-thermal line
broadenings to be measured. We will derive local plasma temperatures and
densities from the line intensities. The spectra will allow accurate
determination of differential emission measure and element abundances
within a variety of corona and transition region structures. These
powerful spectroscopic diagnostics will allow identification
and characterization of magnetic reconnection and wave propagation
processes in the upper solar atmosphere. We will also directly study
the detailed evolution and heating of coronal loops. The EIS instrument
incorporates a unique two element, normal incidence design. The optics
are coated with optimized multilayer coatings. We have selected highly
efficient, backside-illuminated, thinned CCDs. These design features
result in an instrument that has significantly greater effective area
than previous orbiting EUV spectrographs with typical active region
2 - 5 s exposure times in the brightest lines. EIS can scan a field
of 6×8.5 arc min with spatial and velocity scales of 1 arc sec and
25 km s<SUP>−1</SUP> per pixel. The instrument design, its absolute
calibration, and performance are described in detail in this paper. EIS
will be used along with the Solar Optical Telescope (SOT) and the X-ray
Telescope (XRT) for a wide range of studies of the solar atmosphere.
---------------------------------------------------------
Title: NRL EUV Imager: The Solar EUV Atmospheric Research Of The
Corona And Heliosphere (SEARCH) Experiment
Authors: Newmark, J. S.; Doschek, G. A.; Brown, C. M.; Cook, J. W.;
Kilmchuk, J. A.; Korendyke, C. M.; Moses, J. D.; Myers, S. H.; Seely,
J. F.
2007ESASP.641E..74N Altcode:
Achieving the Solar Orbiter primary science goals requires knowledge
of the fine structure of the solar atmosphere from chromospheric
to coronal temperatures, and the structural links between these
different temperature regions. An EUV imager is an ideal instrument
for providing this crucial information, and the Solar Orbiter mission
gives a unique opportunity to investigate the fine structure of the
chromosphere, transition region, and corona at unprecedented high
spatial resolution. We present a concept from the US Naval Research
Laboratory (NRL) for providing an Extreme Ultraviolet (EUV) Imager for
the Solar Orbiter mission, the "Solar EUV Atmospheric Research of the
Corona and Heliosphere" (SEARCH) experiment.
---------------------------------------------------------
Title: Laboratory calibration of the Extreme-Ultraviolet Imaging
Spectrometer for the Solar-B satellite
Authors: Lang, James; Kent, Barry J.; Paustian, Wolfgang; Brown,
Charles M.; Keyser, Christian; Anderson, Mark R.; Case, Giles C. R.;
Chaudry, Rahil A.; James, Adrian M.; Korendyke, Clarence M.; Pike,
C. David; Probyn, Brian J.; Rippington, David J.; Seely, John F.;
Tandy, Jason A.; Whillock, Matthew C. R.
2006ApOpt..45.8689L Altcode:
The laboratory end-to-end testing of the Extreme-Ultraviolet
Imaging Spectrometer (EIS) for the Solar-B satellite is reported. A
short overview of the EIS, which observes in two bands in the
extreme-ultraviolet wavelength range, is given. The calibration
apparatus is described, including details of the light sources
used. The data reduction and analysis procedure are outlined. The
wavelength calibration using a Penning source to illuminate the
aperture fully is presented. We discuss the aperture determination
using a radiometrically calibrated hollow-cathode-based source. We
then give an account of the predicted and measured efficiencies from
consideration of the efficiencies of individual optical elements in
first order, an account of efficiencies out of band when radiation
incident in one band is detected in the other, and efficiencies in
multiple orders. The efficiencies measured in first order for in band
and out of band are compared with the predictions and the sensitivity,
and its uncertainties are derived. Application of the radiometric
calibration is discussed.
---------------------------------------------------------
Title: Optics and mechanisms for the Extreme-Ultraviolet Imaging
Spectrometer on the Solar-B satellite
Authors: Korendyke, Clarence M.; Brown, Charles M.; Thomas, Roger J.;
Keyser, Christian; Davila, Joseph; Hagood, Robert; Hara, Hirohisa;
Heidemann, Klaus; James, Adrian M.; Lang, James; Mariska, John T.;
Moser, John; Moye, Robert; Myers, Steven; Probyn, Brian J.; Seely,
John F.; Shea, John; Shepler, Ed; Tandy, Jason
2006ApOpt..45.8674K Altcode:
The Extreme-Ultraviolet Imaging Spectrometer (EIS) is the first of a
new generation of normal-incidence, two-optical-element spectroscopic
instruments developed for space solar extreme-ultraviolet astronomy. The
instrument is currently mounted on the Solar-B satellite for a planned
launch in late 2006. The instrument observes in two spectral bands,
170-210 Å and 250-290 Å. The spectrograph geometry and grating
prescription were optimized to obtain excellent imaging while still
maintaining readily achievable physical and fabrication tolerances. A
refined technique using low ruling density surrogate gratings and
optical metrology was developed to align the instrument with visible
light. Slit rasters of the solar surface are obtained by mechanically
tilting the mirror. A slit exchange mechanism allows selection among
four slits at the telescope focal plane. Each slit is precisely located
at the focal plane. The spectrograph imaging performance was optically
characterized in the laboratory. The resolution was measured using
the Mg iii and Ne iii lines in the range of 171-200 Å. The He ii line
at 256 Å and Ne iii lines were used in the range of 251-284 Å. The
measurements demonstrate an equivalent resolution of ∼2 arc sec on
the solar surface, in good agreement with the predicted performance. We
describe the EIS optics, mechanisms, and measured performance.
---------------------------------------------------------
Title: The extreme UV imaging spectrometer for the JAXA Solar-B
mission
Authors: Culhane, J. L.; Doschek, G. A.; Watanabe, T.; Smith, A.;
Brown, C.; Hara, H.; Harra, L. K.; James, A. M.; al Janabi, K.;
Kent, B.; Korendyke, C.; Lang, J.; Mariska, J.; Myers, S.; Seely,
J.; Simnett, G.; Tandy, J.; Thomas, R.; Windt, D. L.
2006SPIE.6266E..0TC Altcode: 2006SPIE.6266E..22C
The ISAS/JAXA Solar-B mission includes an Extreme-UV Imaging
Spectrometer (EIS). It detects photons in the wavelength ranges 17 -
21 nm and 25 - 29 nm which include emission lines from several highly
ionised species that exist at temperatures log T = 4.7, 5.6, 5.8,
5.9 and 6.0 - 7.3 K. Instrument throughput is increased substantially
by the use of multilayer coatings optimized for maximum reflectance
in the two selected wavelength bands. The use of back-illuminated
CCDs provides significantly enhanced quantum efficiency over that
previously available from microchannel plate systems. In this paper we
will describe the design and operation of the instrument and present
its performance parameters e.g. spectral and spatial resolution and
sensitivity. Preliminary results of recent calibration measurements
will be described. The role of EIS in the Solar-B mission will be
illustrated with reference to the anticipated observing strategy for
the first three months of the mission which will be outlined.
---------------------------------------------------------
Title: The Extreme Ultraviolet Imaging Spectrometer (EIS) on Solar-B
Authors: Doschek, George A.; Brown, C. M.; Korendyke, C. M.; Mariska,
J. T.; Myers, S. H.; Seely, J. F.; Dere, K. P.; Lang, J.; Culhane,
J. L.; Watanabe, T.
2006SPD....37.3604D Altcode: 2006BAAS...38S.260D
The Extreme Ultraviolet Imaging Spectrometer (EIS) for Solar-B is a
high throughput state-of-the-art instrument designed to obtain solar
spectra and images in two wavelength bands centered near 195 and 270
Angstroms. Traditional spectra can be obtained using narrow slits or
images of solar structures can be obtained in individual spectral
lines using wide slots. Essentially, the instrument obtains images
in wavebands similar to TRACE but in each spectral line within the
waveband. This removes electron temperature ambiguities inherent in
broadband imagers and allows dynamic effects to be detected via Doppler
shifts and densities and other plasma parameters to be measured via
spectroscopic plasma diagnostics. After a brief description of how
the instrument works and a comparison with previous instrumentation
(sensitivity, etc.), the presentation will focus on the science that
can be accomplished with EIS, presented in the form of sample observing
sequences. The focus will be on active regions and solar flares with a
consideration of topics such as temperature and density distributions
in active region loops and their evolution, dynamical motions in active
region loops, the reconnection site in solar flares, and temperature
evolution of multimillion degree flare loops.
---------------------------------------------------------
Title: Calibration of the Soho/Lasco C3 White Light Coronagraph
Authors: Morrill, J. S.; Korendyke, C. M.; Brueckner, G. E.; Giovane,
F.; Howard, R. A.; Koomen, M.; Moses, D.; Plunkett, S. P.; Vourlidas,
A.; Esfandiari, E.; Rich, N.; Wang, D.; Thernisien, A. F.; Lamy, P.;
Llebaria, A.; Biesecker, D.; Michels, D.; Gong, Q.; Andrews, M.
2006SoPh..233..331M Altcode:
We present a detailed review of the calibration of the LASCO C3
coronagraph on the SOHO satellite. Most of the calibration has been
in place since early in the mission and has been utilized to varying
degrees as required by specific analysis efforts. However, using
observational data from the nearly decade-long database of LASCO images,
we have re-evaluated and improved many aspects of the calibration. This
includes the photometric calibration, vignetting function, geometric
distortion, stray light, and exposure and observation times. Using this
comprehensive set of corrections we have generated and made available a
set of calibrated coronal images along with a set of periodic background
images to ease the accessibility and use of the LASCO database.
---------------------------------------------------------
Title: Observing the Solar atmosphere with the Extreme Ultraviolet
Imaging Spectrometer on Solar B
Authors: Korendyke, C. M.; Brown, C.; Dere, K.; Doschek, G.; Klimchuk,
J.; Landi, E.; Mariska, J.; Warren, H.; Lang, J.
2005AGUFMSH41B1124K Altcode:
The Extreme Ultraviolet Imaging Spectrometer (EIS) is part of the
instrument complement on the Solar B satellite, scheduled for launch
in the summer of 2006. The instrument has been calibrated and is
presently mounted on the spacecraft. EIS is the most sensitive EUV
solar spectrometer to be flown. The instrument is the first of a new
generation of two optical element, solar spectrographs. Preliminary
results from the laboratory focussing and calibration of the
instrument will be shown. The instrument wavelength coverage includes
reasonably bright spectral lines emitted by plasmas from 0.1 to 20 MK
in temperature. The wavelength range also provides coronal density
diagnostics. Temperature, density and velocity diagnostics will be
discussed. An example observing program for exploring active region
evolution and dynamics will be discussed.
---------------------------------------------------------
Title: The correlation between features in the solar spectrum near
Mg II and photospheric magnetic fields
Authors: Morrill, J.; Korendyke, C.; Dere, K.
2005AGUSMSP41B..06M Altcode:
During the HRTS-9 flight, spectrograms and spectroheliograms where
obtained of the quiet sun, quiet limb, plage, and sunspots. Previous
analysis of these observations required the correction of a small set
of spectra for instrumental distortions and the absolute intensity
calibration. We have applied these corrections to a larger portion
of the HRTS-9 observations where the spectrograph slit was rastered
across a small region of the sun along the solar equator. This set
of corrected spectrograms has allowed us to generate high spatial and
spectral resolution spectroheliograms of the observed quiet and active
portions of the sun. In addition, with use of a magnetogram taken while
the flight was in progress we have examined the relationship between
the photospheric magnetic field and both Mg II emission at 280 nm and
absorption features in the nearby solar spectrum due to both neutral and
singly ionized species. In this presentation we will present our high
resolution spectroheliograms as well as results showing the relationship
between the magnetic field and several specific spectral features.
---------------------------------------------------------
Title: Structure and Organization of the Upper Chromosphere
Authors: Korendyke, C. M.; Landi, E.; Vourlidas, A.
2005AGUSMSH12A..05K Altcode:
Over its past two flights, the VAULT sounding rocket instrument
obtained a series of subarcsecond resolution images of the solar
disk. These Lyman alpha images resolve and separate structures in
the upper chromosphere. The observed plasmas are concentrated in
larger diameter, optically thick loops. The images taken near the limb
unambiguously identify the height of the upper chromosphere in the quiet
sun. An unexpected level of evolution and activity is present in the
"quiet sun" at small spatial scales. The third flight of the payload
will investigate the interconnectivity of the observed structures with
the photosphere.
---------------------------------------------------------
Title: The Extreme Ultraviolet Imaging Spectrometer on Solar-B
Authors: Mariska, J. T.; Brown, C. M.; Doschek, G. A.; Korendyke,
C. M.; Myers, S. H.; Seely, J. F.; Dere, K. P.; Lang, J.; Culhane,
J. L.; Watanabe, T.
2005AGUSMSP43A..02M Altcode:
The Extreme Ultraviolet Imaging Spectrometer (EIS) is currently under
development for flight on the Japanese Solar-B satellite. EIS uses a
multilayer-coated off-axis telescope mirror and a multilayer-coated
toroidal grating spectrometer to produce stigmatic spectra of solar
regions isolated by a 1024 arcsec high slit. The instrument produces
monochromatic images either by rastering the solar image across a
narrow entrance slit or by using a very wide slit. Half of each optic
is coated to optimize reflectance at 19.5 nm, and the other half to
optimize reflectance at 27.0 nm, with each wavelength range imaged
onto a separate CCD detector. EIS can provide key dynamical and density
diagnostic information. Combining EIS data with observations from the
other instruments on Solar-B should provide a detailed picture of solar
atmospheric processes from the visible surface into the corona. In
this presentation, we provide details of the instrument's expected
performance based on calibration of the individual flight optics and
end-to-end testing at the Rutherford Appleton Laboratory in the UK.
---------------------------------------------------------
Title: Calibration Results for the STEREO/SECCHI COR2 Coronagraphs
Authors: Vourlidas, A.; Plunkett, S.; Korendyke, C.; Gong, Q.; Socker,
D.; Howard, R.
2004AGUFMSH21B0409V Altcode:
The two SECCHI instrument suites aboard the upcoming STEREO mission
include the COR2 coronagraphs which observe the middle/outer corona;
namely, from 2.5 to 15 solar radii. As of the end of August 2004,
both COR2 instruments have been assembled and delivered to the SECCHI
project and their perfomance has been measured and analyzed. The
coronagraphs have met (and in some cases, exceeded) their performance
requirements. Here, we present in detail the results of the calibration
(photometry, polarization, stray light levels, etc) of the COR2
coronagraphs. We compare these new coronagraphs to the LASCO ones
and discuss how they will contribute to the scientific success of the
STEREO mission.
---------------------------------------------------------
Title: Calibration Results for the COR-1 Coronagraph on STEREO/SECCHI
Authors: Thompson, W. T.; Davila, J. M.; Mentzell, E.; Korendyke, C.
2004AGUFMSH21B0408T Altcode:
COR-1 is the inner coronagraph of the Sun Earth Connection Coronal
and Heliospheric Investigation (SECCHI) instrument suite aboard the
two STEREO spacecraft. COR-1 is a classic Lyot internally occulting
coronagraph, observing the solar corona in broadband red light around
656 nm, from 1.35 to 4 solar radii. A linear polarizer is used to
suppress scattered light, and to extract the polarized brightness
signal from the solar corona. Calibration was performed in the Naval
Research Laboratory vacuum tunnel facility previously used for the LASCO
experiment aboard SOHO. We report on the results for scattered light,
photometric calibration, resolution, and polarization. All performance
requirements are met or exceeded. Based on these results, we demonstrate
that COR-1 will be able to carry out its scientific mission.
---------------------------------------------------------
Title: Solar UV Spectral Radiance from SKYLAB
Authors: Morrill, J.; Korendyke, C.; Dere, K.
2004AGUFMSH53A0305M Altcode:
As part of an ongoing NASA-LWS sponsored research program, solar UV
spectral radiance has been determined for the quiet sun at a variety
of center-to-limb positions observed by the SO82B UV spectrograph
on SKYLAB. This has been done using a high quality flatbed scanner
to digitize the SKYLAB film data. The goal of the present program
is to develop a spectral irradiance model that utilizes the full
resolution of the SKYLAB spectra (~ 0.010 nm at 300 nm). The model
requires detailed knowledge of the center-to-limb variation (CLV) at
full resolution over the 200 - 400nm wavelength range. This information
is also required to determine the absolute intensity calibration which
uses full-disk irradiance measurements from UARS (SOLSTICE and SUSIM)
in addition to the CLV. This calibration is then used to derive the disk
center radiance. In addition to the quiet sun, spectra of sunspots and
active regions are also being digitized and an attempt is underway to
derive the CLV for these surface morphologies as well. Further, spectra
at shorter wavelength (~120 - 200nm) are being examined in order to
extend the wavelength coverage of these radiance and CLV results. In
this presentation we will present the details of the analysis methods
and results for the quiet sun. Ongoing work on sunspots and active
regions will be presented as will results involving work on shorter
wavelength spectra.
---------------------------------------------------------
Title: Solar ultraviolet spectro-coronagraph with toroidal varied
line-space (TVLS) grating
Authors: Fineschi, Silvano; Korendyke, Clarence M.; Moses, J. Dan;
Thomas, Roger J.
2004SPIE.5487.1165F Altcode:
This paper describes an instrument for imaging spectroscopy
of ultraviolet (UV) line emission from the solar corona, in the
0.3-1.2x102 nm wavelength range. The optical design for this Ultraviolet
Spectro-Coronagraph (UVSC) is an externally occulted, off-axis Gregorian
telescope where the secondary mirror is a Toroidal Varied Line-Space
(TVLS) grating. A field stop with multiple slits is at the prime focus
of the telescope"s mirror. This multi-slit field stop is the entrance
aperture for the spectrograph. The slits select a number of strips in
the field-of-view (FOV) with enough separation to minimize the spectral
overlap of the UV lines dispersed by the TVLS grating. This type of
gratings allows for a much larger stigmatic FOV (i.e., 3° x 4°)
in both the spatial and spectral direction than that of the Toroidal
Uniform Line-Space (TULS) gratings. The complete imaging of the FOV is
obtained by interpolating the slit images along the spectral dispersion
direction. As an example, this paper discusses the possible use of a
UVSC instrument on HERSCHEL, a NASA sounding-rocket payload, and on
Solar Orbiter (SOLO), an ESA mission. HERSCHEL includes the Sounding
CORona Experiment (SCORE) that comprises a UV Coronagraphic Imager
(UVCI) for narrow-band (i.e., λ/Δλ≈10) imaging of the HeII, 30.4
nm, line. How a spectroscopic capability (i.e., λ/▵λ ≈0.3-1 x
10<SUP>4</SUP>) would enhance the HERSCHEL science is discussed. The
SOLO mission is planned for launch in 2013. Its orbital profile will
bring the spacecraft as close to the Sun as 0.22 A.U. Also SOLO would
represent an ideal and unique platform for a compact UVSC instrument
(i.e., ≈ 1-m length) capable of obtaining simultaneous imaging and
spectroscopy of the UV corona. The expected optical performances are
presented for a UVSC/SOLO optimised for the OVI doublet, 103.2/103.7 nm.
---------------------------------------------------------
Title: A Comparison of the Mg II Index Derived from Estimated and
Observed Solar Spectra
Authors: Morrill, J.; Korendyke, C.; Dere, K.
2004AAS...204.7207M Altcode: 2004BAAS...36..799M
We have estimated values of the Mg II index using a model of solar
spectral irradiance developed at the Naval Research Laboratory. This
model uses Ca II K images and spatially resolved sun spot, quiet sun,
and active sun spectra measured by the HRTS-9 rocket to generate the
estimated spectra. These spectra are compared to observed spectra such
as the UARS-SUSIM and UARS-SOLSTICE data sets. In order to further
compare the observed and estimated spectra, a Mg II index is derived
from these two sets of spectra. In this presentation we will review
the details of the model, discuss the methods of deriving the Mg II
index, and compare the Mg II variability resulting from the observed
and estimated spectra.
---------------------------------------------------------
Title: Performance of multilayer-coated gratings for the
extreme-ultraviolet imaging spectrometer (EIS) for the Solar-B mission
Authors: Seely, John F.; Windt, David L.; Donguy, Soizik; Brown,
Charles; Holland, Glenn; Hunter, William R.; Kowalski, Michael
P.; Kjornrattanawanich, Benjawan; Doschek, George; Mariska, John;
Korendyke, Clarence; Dere, Ken
2004SPIE.5168...12S Altcode:
The measured efficiencies of two flight gratings and the reflectances
of two flight mirrors developed for the Extreme-Ultraviolet Imaging
Spectrometer (EIS) for the Japanese Solar-B mission are presented. Each
optic has two sectors with Mo/Si multilayers that refelct the 17 -
21 nm and 25 - 29 nm wavebands at normal incidence. The efficiencies
that were measured using monochromatic synchrotron radiation are in
good agreement with the calculated efficiencies.
---------------------------------------------------------
Title: Visible, externally occulted coronagraph for Solar Orbiter
Authors: Vives, Sebastien; Lamy, Philippe L.; Korendyke, Clarence
2004SPIE.5171..131V Altcode:
The SIde-Looking Coronagraph (SILC) is one of the solar remote-sensing
instruments proposed for the payload of the Solar Orbiter mission. The
Solar Orbiter is a mission selected in September 2000 by the European
Space Agency (ESA) for the definition study phase. The Solar Orbiter
will describe elliptic orbits with a large range of heliocentric
distance, from 0.21 to 0.6 AU (astronomical units), that is a factor
3 for the geometric conditions and will reach heliographic latitudes
as high as 38 degrees. Furthermore, the spacecraft will have offset
pointing capability so as to target any point of the solar disk. These
constraints (in addition to the severe thermal environment) lead
us to propose an externally occulted coronagraph entirely protected
from direct sunlight by remaining in the shadow of the spacecraft and
looking sideways. The optical design follows the general principles
of an externally-occulted coronagraph adapted to the side-looking
concept. Although SILC loses the full spatial coverage of the corona, it
can observe the inner part of the corona (down to 1.5R) during the whole
mission and compensate the off-pointing of the spacecraft in the two
directions. The performances, resulting from ray-tracing calculations,
are presented here together with the expected stray light level.
---------------------------------------------------------
Title: The SIde-Looking Coronagraph (SILC) for the Solar Orbiter
mission
Authors: Vives, S.; Lamy, P.; Korendyke, C.
2004cosp...35..951V Altcode: 2004cosp.meet..951V
The SIde-Looking Coronagraph (SILC) is one of the solar remote-sensing
instruments proposed for the payload of the Solar Orbiter mission
(European Space Agency, ESA). The Solar Orbiter will describe elliptic
orbits with a large range of heliocentric distance, from 0.21 to
0.6 AU, that is a factor 3 for the geometric conditions, and will
reach heliographic latitudes as high as 38 degrees. Furthermore, the
spacecraft will have offset pointing capability so as to target any
point of the solar disk. These specificities (in addition to the severe
thermal environment) are very restrictive for a coronagraph and lead
us to propose an externally occulted coronagraph entirely protected
from direct sunlight by remaining in the shadow of the spacecraft and
looking sideways. The optical design follows the general principles
of an externally-occulted coronagraph adapted to the side-looking
concept. Although SILC loses the full spatial coverage of the corona,
it can observe the inner part of the corona (down to 1.5 solar radii)
during the whole mission and compensate the off-pointing of the
spacecraft in the two directions. The performances, resulting from
ray-tracing calculations, will be presented together with the first
measurements of the stray light level.
---------------------------------------------------------
Title: LASCO C2 and C3 Level-1 Images: Calibration and Pipeline
Processing
Authors: Thernisien, A. F.; Morrill, J.; Llebaria, A.; Rich, N.;
Vourlidas, A.; Esfandiari, E.; Wang, D.; Korendyke, C.; Moses, D.;
Biesecker, D.; Bout, M.; Lamy, P.; Howard, R. A.
2003AGUFMSH41B0461T Altcode:
The LASCO C2 and C3 coronagraphs have provided coronal observations
since May, 1996. Initial calibrations have been available during most
of this time period. We have subsequently completed a re-evaluation
and refinement of these calibration procedures. We are now able
to present the final version of the level-1 data using the latest
improvements from in-flight calibration results. Further details
on the LASCO calibration and level-1 data access are presented at
http://lasco-www.nrl.navy.mil/level_1/lascocal_index.html. In this
presentation we will sum up the different aspects of the LASCO
C2-C3 image corrections such as vignetting, absolute photometry,
time corrections, geometric distortion, sun center position, and
spacecraft orientation.
---------------------------------------------------------
Title: High-Resolution Views of the Solar Atmosphere
Authors: Vourlidas, A.; Korendyke, C.
2003SPD....34.2009V Altcode: 2003BAAS...35..845V
The study of many of the outstanding phenomena of the solar atmosphere
(coronal heating, flares and coronal mass ejection) has persistently
shown that observations of physical processes at ever smaller scales
are needed for their understanding. Here I report on the results from
the latest NRL sounding rocket payload, the Very Advanced ULtraviolet
Telescope (VAULT). In two successful flights, the instrument achieved
0.33 arcsecond resolution, the highest ever from a space platform. VAULT
obtained spectrally pure images of the upper chromosphere/lower
transition region in the Lya line (1216A). A number of space-borne
and ground-based obsrvatories supported the VAULT flights. The first
results from the analysis of these datasets will be presented.
---------------------------------------------------------
Title: Expected Performance of the Extreme Ultraviolet Imaging
Spectrometer on Solar-B
Authors: Mariska, J. T.; Brown, C. M.; Dere, K. P.; Doschek, G. A.;
Korendyke, C. M.; Myers, S. H.; Seely, J. F.; Culhane, J. L.;
Watanabe, T.
2003SPD....34.2006M Altcode: 2003BAAS...35..845M
The Extreme Ultraviolet Imaging Spectrometer (EIS) is currently under
development for flight on the Japanese Solar-B satellite. EIS uses a
multilayer-coated off-axis telescope mirror and a multilayer-coated
toroidal grating spectrometer to produce stigmatic spectra of solar
regions isolated by a 1024 arcsec high slit. The instrument produces
monochromatic images either by rastering the solar image across a
narrow entrance slit or by using a very wide slit. Half of each optic
is coated to optimize reflectance at 19.5 nm, and the other half to
optimize reflectance at 27.0 nm, with each wavelength range imaged
onto a separate CCD detector. <P />In this presentation we provide an
update on the EIS hardware development and show details of the expected
performance of the instrument in solar quiet regions, active regions,
and flares.
---------------------------------------------------------
Title: High Resolution Limb Darkening Function Near 2800 /AA/
Measured by HRTS
Authors: Morrill, J. S.; Dere, K. P.; Korendyke, C. M.
2003SPD....34.1909M Altcode: 2003BAAS...35..843M
We are currently developing an empirical model of solar spectral
irradiance varaibility. This model will combine ground based
observations of the areas and locations of plage and sunspots with
measured wavelength dependent contrast factors in order to estimate
the solar spectrum. One important component of this model is the
wavelength dependent limb darking function that must be determined
at high resolution. Using quiet sun spectra near Mg II at about 2800
/AA/ measured by the NRL HRTS instrument, we have recently determined
this function for the quiet sun. This function shows many features
similar to those seen in the active region contast that we have
reported earlier. In this presentation we will discuss the method of
determining the limb darkening function in the 2765 -2885 /AA/ region
and it's impact on the irradiance model.
---------------------------------------------------------
Title: The Reconnection And Microscale (RAM) Solar-Terrestrial Probe
Authors: Bookbinder, Jay A.; DeLuca, Edward; Cheimets, Peter; Golub,
Leon; Hassler, Donald M.; Korendyke, Clarence M.; Glenn, Paul E.;
Silver, Eric H.
2003SPIE.4853..436B Altcode:
A hot, magnetized plasma such as the solar corona has the property that
much of the physics governing its activity takes place on remarkably
small spatial and temporal scales, while the response to this activity
occurs on large scales. Observations from SMM, TRACE, SOHO and Yohkoh
have shown that typical solar active regions have loops ranging in
temperature from 0.5 to 10 MK, and flares up to 40MK. The spatial
and temporal domains involved have been heretofore inaccessible to
direct observations from Earth, so that theory has relied heavily on
extrapolations from more accessible regimes, and on speculation. The
RAM Solar-Terrestrial Probe consists of a set of carefully selected
imaging and spectroscopic instruments that enable definitive studies
of the dynamics and energetics of the solar corona.
---------------------------------------------------------
Title: Calibration of the LASCO C3 Coronal Images
Authors: Morrill, J.; Biesecker, D.; Esfandiari, A.; Korendyke, C.;
Moses, D.; Rich, N.; Vourlidas, A.; Wang, D.; Howard, R. A.; Lamy,
P.; Llebaria, A.; Thernisien, A.
2002AAS...200.5503M Altcode: 2002BAAS...34R.732M
The LASCO C3 coronagraph has provided coronal observations since May,
1996. Preliminary calibrations have been available during most of this
time period. However, some aspects of the calibration have required
re-evaluation and we are just completing a complete review of the
calibration procedure for these images. In this presentation we will
discuss the steps required to correct LASCO C3 images. This includes
corrections required by both optical and electrical characteristics
of the instrument as well as timimg and spacecraft pointing driven
correctons.
---------------------------------------------------------
Title: On the Correlation between Coronal and Lower Transition Region
Structures at Arcsecond Scales
Authors: Vourlidas, A.; Klimchuk, J. A.; Korendyke, C. M.; Tarbell,
T. D.; Handy, B. N.
2001ApJ...563..374V Altcode:
We compare the morphology of active region structures observed in
the 171 Å (T~9×10<SUP>5</SUP> K) and Lyα (T~2×10<SUP>4</SUP> K)
lines. The coronal data were obtained by the Transition Region and
Coronal Explorer (TRACE) in support of the Very High Angular Resolution
Ultraviolet Telescope (VAULT) sounding rocket launch, which acquired
subarcsecond resolution images of an active region in the Lyα line,
on 1999 May 7. Using a pair of calibrated, nearly simultaneous images,
we find that: (i) a very good correlation exists between the Lyα and
171 Å intensities in the TRACE moss regions, (ii) we can identify
several identical structures in some (but not all) moss areas, and
(iii) the correlations are greatly reduced at the footpoints of the
171 Å large-scale loops. We derive a lower limit for the Lyα emission
measure, under the assumption of effectively optically thin emission,
and compare it to the 171 Å emission measure. As in previous studies,
we find an excess of Lyα material compared to the amount expected
for a thermal conduction-dominated corona-chromosphere transition
region, even for structures that appear to be identical in the two
wavelengths. This result implies that some other mechanism besides
classical heat conduction from the corona must contribute to the
observed Lyα intensities. The observations do not support the idea
of a physically distinct cool loop component within active regions.
---------------------------------------------------------
Title: Solar Irradiance Variability Modeled Near Mg II Using Plage
and Sunspot Contrast Factors Measured by HRTS
Authors: Morrill, J. S.; Dere, K. P.; Korendyke, C. M.; Floyd, L. E.
2001AGUFMSH11C0733M Altcode:
Empirical models of solar spectral irradiance varaibility combine areas
and locations of plage and sunspots with wavelength dependent contrast
factors in order to estimate the solar spectrum. At UV wavelengths,
these models have relied on estimated or calculated contrast factors
that are often at low resolution. Using quiet sun, plage, and sunspot
spectra near Mg II at ~ 2800Å measured by the NRL HRTS instrument,
we have recently determined the wavelength dependent contrast factors
for plage and sunspots. In this presentation we will discuss the use of
measured contrast factors in a spectral irradiance model of the 2765 -
2885Å region and the preliminary comparisons of model results with
SUSIM observations. These comparisons will examine spectral irradiance
variations on solar rotational and solar cycle time scales.
---------------------------------------------------------
Title: The Sources of Solar Ultraviolet Variability between 2765
and 2885 Å: Mg I, Mg II, Si I, and Continuum
Authors: Morrill, J. S.; Dere, K. P.; Korendyke, C. M.
2001ApJ...557..854M Altcode:
The variation of the solar spectrum between 2000 and 4000 Å is a
major component of the total irradiance variability of the Sun. Recent
analyses suggest that variations in the solar ultraviolet flux at
these wavelengths account for about 30% of the total solar irradiance
variability. Most estimates of solar spectral irradiance variability in
the ultraviolet are based on the ratio of the intensity of features such
as solar plages and sunspots to the intensity of the quiet Sun. These
ratios are referred to as contrast factors. To a large degree, contrast
factors at ultraviolet wavelengths have not been measured. We present
measurements of the average intensities of plage, sunspot, and quiet-Sun
regions in the spectral range between 2765 and 2885 Å, derived from
high spatial and spectral resolution spectra obtained during the ninth
rocket flight of the High Resolution Telescope and Spectrograph in
1995. From these average spectra, plage and sunspot contrast factors
are determined. To our knowledge, these are the first contrast factors
at these wavelengths derived from measured solar intensities. These
spectra show a large contrast in the Mg I, Mg II, and Si I Fraunhofer
lines and a much smaller contrast (1.01+/-0.015 to 1.04+/-0.04) in
the line-blanketed continuum. Contrast factors are also determined
for three intensity levels of the quiet Sun as well as for a single
sunspot. Many fine spectral features in the contrast factors can be
attributed to weak Fraunhofer lines of Cr II, Fe I, Fe II, and Mg I.
---------------------------------------------------------
Title: High-resolution Imaging of the Upper Solar Chromosphere:
First Light Performance of the Very-high-Resolution Advanced
ULtraviolet Telescope
Authors: Korendyke, C. M.; Vourlidas, A.; Cook, J. W.; Dere, K. P.;
Howard, R. A.; Morrill, J. S.; Moses, J. D.; Moulton, N. E.; Socker,
D. G.
2001SoPh..200...63K Altcode:
The Very-high-resolution Advanced ULtraviolet Telescope (VAULT)
experiment was successfully launched on 7 May 1999 on a Black Brant
sounding rocket vehicle from White Sands Missile Range. The instrument
consists of a 30 cm UV diffraction limited telescope followed by a
two-grating, zero-dispersion spectroheliograph tuned to isolate the
solar Lα emission line. During the flight, the instrument successfully
obtained a series of images of the upper chromosphere with a limiting
resolution of ∼ 0.33 arc sec. The resulting observations are the
highest-resolution images of the solar atmosphere obtained from space
to date. The flight demonstrated that sub-arc second ultraviolet
images of the solar atmosphere are achievable with a high-quality,
moderate-aperture space telescope and associated optics. Herein,
we describe the payload and its in-flight performance.
---------------------------------------------------------
Title: Ultra-High Resolution Observations of the Upper Chromosphere:
First Results From the NRL VAULT Sounding Rocket Payload
Authors: Vourlidas, A.; Korendyke, C. M.; Dere, K. P.; Klimchuk, J. A.
2001AGUSM..SP61A03V Altcode:
The Very high resolution Advanced ULtraviolet Telescope (VAULT) is
a new spectroscopic imaging instrument. The instrument was launched
on May 7, 1999 as a sounding rocket payload. The goal of the first
VAULT flight was to obtain sub-arcsecond images of the Sun in the
light of Lya (1216 Å). VAULT directly imaged an active region plage,
fliaments and the fine structures in the supergranule boundaries and
network with the unprecented spatial resolution of 0.33 arcseconds. We
present the VAULT images and the first results from the comparison of
the Lya data to observations from other instruments and in particular
with a sequence of TRACE 171 Å images taken during the VAULT flight.
---------------------------------------------------------
Title: The Extreme Ultraviolet Imaging Spectrometer on Solar-B
Authors: Mariska, J. T.; Brown, C. M.; Dere, K. P.; Doschek, G. A.;
Korendyke, C. M.; Culhane, J. L.; Watanabe, T.
2001AGUSM..SH41A12M Altcode:
Emission lines in the extreme ultraviolet spectral region provide a
sensitive probe of the high-temperature plasma in the solar transition
region and corona. Simultaneously achieving high spatial, spectral, and
temporal resolution in this wavelength region has been challenging. We
describe the design and capabilities of the Extreme Ultraviolet
Imaging Spectrometer (EIS) planned for flight on the Japanese Solar-B
satellite. EIS consists of a multilayer-coated off-axis telescope
mirror and a multilayer-coated toroidal grating spectrometer. The
telescope mirror forms a solar image on the spectrometer entrance slit
assembly and the spectrometer forms stigmatic spectra of the solar
region isolated by the 1024 arcsec high slit. The instrument includes
thin-film aluminum filters to reject longer wavelength radiation and
CCD detectors at the focal plane. Articulation of the primary mirror
provides roughly 1600 arcsec of east-west coarse pointing freedom
and 360 arcsec of fine east-west motion for rastering. Monochromatic
images are formed either by rastering the solar image across a narrow
entrance slit or by using a very wide slit. Half of each optic is
coated to optimize reflectance at 19.5 nm, and the other half to
optimize reflectance at 27.0 nm. Each wavelength range is imaged onto
a separate CCD detector. The EIS spectral range contains emission lines
formed over a temperature range from roughly 0.1 to 20 MK. Bright lines
in the selected wavelength bands will yield precision measurements of
line-of-sight velocities and nonthermal plasma motions. This spectral
range also includes several pairs of density-sensitive lines.
---------------------------------------------------------
Title: High Resolution Observations of Solar Spectral Variability
Near Mg II Measured by HRTS
Authors: Morrill, J. S.; Dere, K. P.; Korendyke, C. M.
2001AGUSM..SP32B03M Altcode:
The HRTS-9 rocket flight occurred on April 18, 1995 and made
measurements of solar spectral variability near the Mg II h and k
lines. These observations include high spatial and spectral resolution
spectrograms as well as spectroheliograms in four FUV passbands and
H-alpha. The spectrograms cover the wavelength range 2665 to 2885Å
with a spectral resolution of .2Å and a spatial resolution of 1
arc-second along a 900 arc-second slit. The most prominent features
in this spectral range include the strong Mg II h and k lines near
2800 Å, the Mg I and Si I Fraunhofer lines near 2850 and 2880Å,
respectively, and the line-blanketed quasi-continuum region. During
the HRTS-9 flight, spectrograms and spectroheliograms where obtained
of the quiet sun, quiet limb, plage, and sunspots. In addition to
instrumental corrections, we have recently applied an absolute intensity
calibration to the HRTS-9 data derived from SUSIM/ATLAS-3 and SUSIM/UARS
observations. The analysis of these calibrated data has focused on
the spectral variability of the above surface features and how these
observations impact solar irradiance variability. Specifically, we
examine the contrast variation of the plage and sunspot compared to the
quiet sun as well as contrast variation within the quiet sun. In this
presentation we will discuss the details of the observed spectra and
wavelength dependent contrast factors. This will include a comparison
of our present results with earlier estimates of plage contrast in this
wavelength region and a discussion of the fine structures observed at
high spectral resolution.
---------------------------------------------------------
Title: Extreme-ultraviolet imaging spectrometer designed for the
Japanese Solar-B satellite
Authors: Culhane, J. L.; Korendyke, Clarence M.; Watanabe, Tetsuya;
Doschek, George A.
2000SPIE.4139..294C Altcode:
The Extreme-ultraviolet Imaging Spectrometer combines, for the first
time, high spectral, spatial and temporal resolution in a satellite
based, solar extreme ultraviolet instrument. The instrument optical
design consists of a multilayer-coated off- axis paraboloid mirror
telescope followed by a toroidal grating spectrometer. The instrument
includes thin film aluminum filters to reject longer wavelength solar
radiation and employs CCD detectors at the focal plane. The telescope
mirror is articulated to allow sampling of a large fraction of the
solar surface from a single spacecraft pointing position. Monochromatic
images are obtained either by rastering the solar image across the
narrow entrance slit or by using a wide slit or slot in place of
the slit. Monochromatic images of the region centered on the slot are
obtained in a single exposure. Half of each optic is coated to maximize
reflectance at 195 angstrom; the other half is coated to maximize
reflectance at 270 angstrom. The two EUV wavelength bands were selected
to optimize spectroscopic plasma diagnostic capabilities. Particular
care was taken to choose wavelength ranges with relatively bright
emission lines to obtain precision line of sight and turbulent bulk
plasma velocity measurements from observed line profiles. The EIS
spectral range contains emission lines formed over a temperature
range from approximately 10<SUP>5</SUP> - 10<SUP>7</SUP> K. The
wavelength coverage also includes several density sensitive emission
line pairs. These line pairs provide spatial resolution independent
density diagnostics at nominal coronal temperatures and densities. Each
wavelength band is imaged onto a separate CCD detector. The main EIS
instrument characteristics are: wavelength bands -- 180 - 204 angstrom
and 250 - 290 angstrom; spectral resolution -- 0.0223 angstrom/pixel
(23 - 34 km/second-pixel); slit dimensions -- 4 slits: 1 X 1024 arc-
seconds and 50 X 1024 arc-seconds with two positions unspecified as
of this writing; fine raster range -- >6 arc-minutes on the sun;
coarse raster range -- > 1600 arc- seconds on the sun; largest
spatial field of view in a single exposure -- 50 X 1024 arc-seconds;
nominal time resolution for active region velocity studies -- 3.4s. The
Solar-B satellite is scheduled for launch in August 2005 into a nominal
600 km sun-synchronous orbit.
---------------------------------------------------------
Title: NASA Solar Terrestrial Relations Observatory (STEREO) mission
heliospheric imager
Authors: Socker, Dennis G.; Howard, Russell A.; Korendyke, Clarence
M.; Simnett, George M.; Webb, David F.
2000SPIE.4139..284S Altcode:
The NASA Solar Terrestrial Relations Observatory (STEREO) mission will
place two spacecraft into solar orbits with sufficient separation
to provide remote sensing instruments with a stereoscopic view of
the heliosphere extending from the lower solar corona to beyond one
astronomical unit. Analysis of the stereographs returned from the two
spacecraft will allow solar physicists to infer the three-dimensional
structure of small and large components of the corona. The Sun Earth
Connection Coronal and Heliospheric Investigation (SECCHI) suite of
remote sensing instruments includes a Heliospheric Imager (HI) to view
the heliosphere in the interval from 12 to 215 solar radii. The HI
will obtain the first stereographic images of coronal mass ejections in
interplanetary space. Of particular interest is the subset of coronal
mass ejections that propagate through the heliosphere and ultimately
impact the earth. This paper presents the design concept for this new
wide field coronagraph.
---------------------------------------------------------
Title: In-flight performance of the Very high Angular resolution
ULtraviolet Telescope sounding rocket payload
Authors: Korendyke, Clarence M.; Vourlidas, A.; Cook, John W.; Dere,
Kenneth P.; Feldman, R.; Howard, Russell A.; Lilley, D. N.; Morrill,
Jeff S.; Moses, J. Daniel; Moulton, Norman E.; Moye, Robert W.;
Roberts, D. E.; Shepler, E. L.; Smith, J. K.; Socker, Dennis G.;
Spears, T. R.; Waymire, R. S.; Brown, Wayne E.; Tarbell, Theodore D.;
Berger, Tom; Handy, Brian N.
2000SPIE.4139..340K Altcode:
The Very high Angular Resolution ULtraviolet Telescope experiment was
successfully launched on May 7, 1999 on a Black Brant sounding rocket
vehicle from White Sands Missile Range. The instrument consists of a
30 cm UV diffraction limited telescope followed by a double grating
spectroheliograph tuned to isolate the solar Lyman (alpha) emission
line. During the flight, the instrument successfully obtained a series
of images of the upper chromosphere with a limiting resolution of
approximately 0.33 arc-seconds. The resulting observations are the
highest resolution images of the solar atmosphere obtained from space
to date. The flight demonstrated that subarc-second ultraviolet images
of the solar atmosphere are achievable with a high quality, moderate
aperture space telescope and associated optics. Herein, we describe
the payload and its in- flight performance.
---------------------------------------------------------
Title: Instrumentation for UV/EUV Astronomy and Solar Missions
Authors: Fineschi, Silvano; Korendyke, Clarence M.; Siegmund, Oswald
H.; Woodgate, Bruce E.
2000SPIE.4139.....F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar UV Irradiance Variability Observed at High Spatial and
Spectral Resolution by HRTS
Authors: Morrill, J. S.; Dere, K. P.; Korendyke, C. M.
2000SPD....31.0128M Altcode: 2000BAAS...32..806M
The HRTS-9 rocket flight occured on April 18, 1995 and was configured
to study the sources of solar variablity by observing ultraviolet
emission patterns near the Mg II h and k lines. These observations
include high spatial and spectral resolution spectrograms as
well as spectroheliograms in four FUV passbands and H-alpha. The
spectrograms cover the wavelength range 2665 to 2885 Angstroms \ with
a spectral resolution of .2 Angstroms \ and a spatial resolution of 1
arc-second along a 900 arc-second slit. Prominent spectral features
in this wavelength range include the Mg II h and k lines near 2800
Angstroms, the strong Mg I and Si I Fraunhofer lines near 2850 and
2880 Angstroms, respectively, and the line-blanketed quasi-continuum
region. HRTS-9 observations included the quiet sun, quiet limb,
plage, and sunspots. The analysis of this data set has focused on
the spatial intensity variability of the features as a function of
wavelength with particular regard for how these will affect solar
variability. Specifically, we examine the contrast variation of
the plage and sunspot compared to the quiet sun as well as contrast
variation within the quiet sun. The observed sunspot spectrum shows
the characteristic decrease in the quasi-continuum, the non-reversed
Mg II h and k line shapes as well as the enhancement in the Mg II
h and k core emissions over that observed in the quiet sun. In this
presentation we will discuss the wavelength dependent contrasts of
the plage and quiet sun regions, the characteristics of the observed
sunspot spectrum, and the implications on solar variability.
---------------------------------------------------------
Title: Search for Velocity Variations in Fe XIV 5304 A&ring
Coronagraph Observations Near Activity Minimum
Authors: Cook, J. W.; Socker, D. G.; Korendyke, C. M.; Howard, R. A.;
Brueckner, G. E.; Karovska, M.; Wood, B. E.
2000AdSpR..25.1883C Altcode:
The LASCO C1 coronagraph on the SOHO satellite observes the solar
corona from 1.1 to 3.0 Ro, and contains a Fabry-Perot interferometer
which can image the corona in the 1.8 million K Fe XIV green line. We
designed an observing program with reduced spatial coverage and reduced
profile coverage at only three wavelengths to study coronal heating
in off-limb structures at high temporal resolution. We illustrate the
observations from 31 March 1997 of a bright loop system above an active
region off the northeast limb
---------------------------------------------------------
Title: Calibrated H I Lyman α Observations with TRACE
Authors: Handy, B. N.; Tarbell, T. D.; Wolfson, C. J.; Korendyke,
C. M.; Vourlidas, A.
1999SoPh..190..351H Altcode:
Since shortly after launch in April 1998, the Transition Region and
Coronal Explorer (TRACE) observatory has amassed a collection of H
i Lα (1216 Å) observations of the Sun that have been not only of
high spatial and temporal resolution, but also span a duration in
time never before achieved. The Lα images produced by TRACE are,
however, composed of not only the desired line emission, but also
local ultraviolet continuum and longer wavelength contamination. This
contamination has frustrated attempts to interpret TRACE observations
in H i Lα. The Very Advanced Ultraviolet Telescope (VAULT) sounding
rocket payload was launched from White Sands Missile range 7 May 1999
at 20:00 UT. The VAULT telescope for this flight was a dedicated H i
Lα imaging spectroheliograph. We use TRACE observations in the 1216
Å and 1600 Å channels along with observations from the VAULT flight
to develop a method for removing UV continuum and longer wavelength
contamination from TRACE Lα images.
---------------------------------------------------------
Title: Concept Study Report: Extreme-Ultraviolet Imaging Spectrometer
Solar-B
Authors: Doschek, George A.; Brown, Charles M.; Davila, Joseph M.;
Dere, Kenneth P.; Korendyke, Clarence M.; Mariska, John T.; Seely,
John F.
1999STIN...0011153D Altcode:
We propose a next generation Extreme-ultraviolet Imaging Spectrometer
(EIS) that for the first time combines high spectral, spatial, and
temporal resolution in a single solar spectroscopic instrument. The
instrument consists of a multilayer-coated off-axis telescope mirror
and a multilayer-coated grating spectrometer. The telescope mirror
forms solar images on the spectrometer entrance slit assembly. The
spectrometer forms stigmatic spectra of the solar region located
at the slit. This region is selected by the articulated telescope
mirror. Monochromatic images are obtained either by rastering the solar
region across a narrow entrance slit, or by using a very wide slit
(called a slot) in place of the slit. Monochromatic images of the
region centered on the slot are obtained in a single exposure. Half
of each optic is coated to maximize reflectance at 195 Angstroms; the
other half to maximize reflectance at 270 Angstroms. The two Extreme
Ultraviolet (EUV) wavelength bands have been selected to maximize
spectral and dynamical and plasma diagnostic capabilities. Spectral
lines are observed that are formed over a temperature range from about
0.1 MK to about 20 MK. The main EIS instrument characteristics are:
wavelength bands - 180 to 204 Angstroms; 250 to 290 Angstroms; spectral
resolution - 0.0223 Angstroms/pixel (34.3km/s at 195 Angstroms and
23.6 km/s at 284 Angstroms); slit dimensions - 4 slits, two currently
specified dimensions are 1" x 1024" and 50" x 1024" (the slot);
largest spatial field of view in a single exposure - 50" x 1024";
highest time resolution for active region velocity studies - 4.4 s.
---------------------------------------------------------
Title: LASCO/SOHO Observations of Dust in the Outer Solar Corona
Authors: Kimura, H.; Mann, I.; Goldstein, B.; Korendyke, C.; Howard, R.
1999DPS....31.5501K Altcode:
The solar F-corona emission is comprised of solar radiation scattered
by dust particles and thermal radiation emitted from near-solar dust
particles. The visible brightness is mainly produced by scattering
at medium scattering angles from particles near the Sun and by
enhanced forward scattering from particles near the observer. The
infrared brightness originates from the thermal emission from hot
particles near the Sun. Studies of the F-corona are usually limited
by the influence of atmospheric stray light and by difficulties of
the separation of the K-corona, produced by sunlight scattered at
electrons. The K-corona decreases steeply with increasing elongation
and has a smaller contribution to the outer coronal brightness. This
outer corona is observed from the SOHO satellite where the lack of
atmospheric stray light and an optimized suppression of instrumental
stray light in the LASCO coronagraph allow for the detection of the
coronal brightness as far out as about 30 solar radii from the center
of the Sun. These observations yield the opportunity to study the
properties of interplanetary dust in the inner solar system. We will
present preliminary results from the analysis of the data from the LASCO
C3 coronagraph at distances from 10 to 30 solar radii from the center
of the Sun in 3 wavelength intervals between 0.4 and 1.1 micron. We
compare the data to brightness calculations in order to discuss the
distribution of dust grains in the inner solar system. The Solar
Heliospheric Observatory, SOHO, is a joint scientific space mission
developed by ESA and NASA. The Large Angle Spectrometric Coronagraph
(LASCO) was developed and is operated jointly by the Naval Research
Laboratory (USA), the Max-Planck-Institut fur Aeronomie (Germany),
the Laboratoire d'Astronomie Spatiale (France) and the University of
Birmingham (UK).
---------------------------------------------------------
Title: LASCO/SOHO observations of dust in the outer solar corona.
Authors: Kimura, H.; Mann, I.; Goldstein, B.; Korendyke, C.; Howard, R.
1999BAAS...31.1159K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: HRTS Observations of Solar Fine Scale Structures in the Near-UV
Authors: Morrill, J. S.; Dere, K. P.; Korendyke, C. M.
1999AAS...194.9311M Altcode: 1999BAAS...31..990M
The NRL High Resolution Telescope and Spectrograph (HRTS) obtains
ultraviolet spectra, ultraviolet spectroheliograms and H alpha
spectroheliograms at a spatial resolution of about 1 arc-second along
a 900 arc-second slit. The HRTS-9 rocket flew on April 18, 1995 during
the declining phase of the solar cycle. The HRTS-9 instrument and
observing program were tailored to observe emission patterns inthe
ultraviolet for the purpose of studying solar variability. Observation
targets included the quiet sun, active regions and the quiet limb. The
wavelength range of HRTS-9 spectrograph was from 275 nm to 290 nm. Some
of the prominent spectral features in this wavelength range are the
Mg II h and k lines at 280 nm, the strong Mg I Fraunhofer line at 285
nm, and the continuum. The ultraviolet spectroheliograph obtained
images of a portion of the sun at wavelengths corresponding to a
range of temperatures: 1550 (C IV), 1540 (Si I), 1560 (C I), and 1600
(continuum). The primary goal of the HRTS-9 rocket program was to
examine the origin of the total solar variability in the intensity
variations of solar structures in the near ultraviolet on a variety
of spatial scales. The HRTS-9 data reveals the fine structure of the
quiet sun, plage, and sun spots in the near ultraviolet. In addition,
active region contrast factors are determined for comparison with
modes of full disk ultraviolet variability based on SUSIM and SOLTICE
observations from UARS.
---------------------------------------------------------
Title: Solar Polar Imager
Authors: Moses, D.; Dere, K. P.; Howard, R. A.; Korendyke, C. M.;
Socker, D. G.; Wang, Y. -M.; Goldstein, B. E.; Liewer, P. E.
1999AAS...194.7613M Altcode: 1999BAAS...31..958M
Observation of the global coronal and magnetic field structure of
the Sun requires coronal imaging and magnetograms from a perspective
out of the ecliptic. While the upcoming Solar Terrestrial Relations
Observatory (STEREO) mission will provide a great advance in the
understanding of the three-dimensional structure of the corona and
interplanetary medium, the orientation of the Sun's large scale magnetic
axis of symmetry with the STEREO spacecraft separation defines the
limits of this mission. The global structure of the streamer belts,
polar coronal holes and coronal plumes all reflect the symmetry of
the large scale solar magnetic field. Observations of Coronal Mass
Ejections (CMEs) from the LASCO and EIT instruments on the Solar and
Heliospheric Observatory (SOHO) indicate the need for synoptic coronal
imaging out of the ecliptic (Solar Polar Imager), as well as in stereo
pairs in the ecliptic (STEREO), for advancement in the understanding
of the origins and consequences of CMEs. The SOHO MDI has shown the
need for observations of the evolution of the polar magnetic fields
and convection patterns to understand the generation and transport
of the solar magnetic fields. Finally, the Ulysses mission has shown
the need for polar coronal imaging and magnetograms for understanding
the source of the solar wind. Ulysses has demonstrated the need for
on-board in situ particles and fields instruments as a link to the
remote sensing observations. Lightweight and compact instrumentation for
these observations has already been demonstrated technically. An orbital
mission involving a Jupiter assist such as Ulysses is also technically
demonstrated, although the duration of the polar observations is limited
to the point of degrading the studies of solar cycle evolution. An
orbital mission involving a circularized polar orbit is possible with
the use of solar-sail propulsion, but this involves technology that
has yet to be demonstrated.
---------------------------------------------------------
Title: Extension of the Polar Coronal Hole Boundary into
Interplanetary space
Authors: Woo, Richard; Habbal, Shadia Rifai; Howard, Russell A.;
Korendyke, Clarence M.
1999ApJ...513..961W Altcode:
White-light measurements made by the SOHO LASCO C2 and C3 coronagraphs
and the Mk III Mauna Loa K-coronameter, ranging from 1.15 to 30
R<SUB>solar</SUB>, have been combined with Kitt Peak daily He I
1083 nm coronal hole maps, and full Sun Yohkoh soft X-ray images,
to show that the boundaries of polar coronal holes, as determined
by measurements of path-integrated density, extend approximately
radially into interplanetary space. These results are in contrast to
the long-standing view that the boundaries of polar coronal holes
diverge significantly beyond radial, evolving around the edges of
streamers. The combined observations also show that the corona is
dominated by raylike structures as small as a few degrees in angular
size with respect to Sun center, originating from both coronal holes
and the quiet Sun. This analysis provides further support for results
originally derived from radio occultation measurements, namely, that
the coronal density projects itself almost radially from the Sun into
the outer corona, implying that open field lines abound in the quiet
Sun from which the fast wind can alsooriginate.
---------------------------------------------------------
Title: Corrals, hubcaps, and crystal balls: some new designs for
very-wide-angle visible-light heliospheric imagers
Authors: Buffington, Andrew; Hick, P. P.; Jackson, Bernard V.;
Korendyke, Clarence M.
1998SPIE.3442...77B Altcode:
Emerging techniques allow instruments to view very large sky areas,
a hemisphere or more, in visible light. In space, such wide-angle
coverage enables observation of heliospheric features form close to
the Sun to well beyond Earth. Observations from deep-space missions
such as Solar Probe, Stereo, and Solar Polar Sail, coupled with
observations near Earth, permit 3D reconstruction of solar mass
ejections and co-rotating structures, discovery and study of new comets
and asteroids, and detailed measurements of brightness variations in
the zodiacal cloud. Typical heliospheric features have 1 percent or
less of ambient brightness, so visible-light cameras must deliver <
0.1 percent photometry and be well protected from stray background
light. When more than a hemisphere of viewing area is free of bright
background-light sources, we have shown that corral-like structures
with several vane-like walls reduces background light illuminating
to wide-angle optical system by up to ten orders of magnitude. The
optical system itself typically provides another five orders of
surface-brightness reduction. With CCDs as the light-detection device,
images of point-like sources must cover typically 100 pixels to average
down sub-pixel response gradients and provide the above 0.1 percent
photometry. With present-day CCDs this requires images of order 1 degree
in angular size. Tolerating such large images in turn enables wide-angle
sky coverage using simple reflecting and refracting optical systems
such as convex spherical reflectors, toroids and thick lenses. We show
that combining these with light- reducing corrals yields practical,
light-weight instruments suitable for inclusion on deep-space probes.
---------------------------------------------------------
Title: Search for Brightness Variations in Fe XIV Coronagraph
Observations of the Quiescent Solar Corona
Authors: Wood, B. E.; Karovska, M.; Cook, J. W.; Brueckner, G. E.;
Howard, R. A.; Korendyke, C. M.; Socker, D. G.
1998ApJ...505..432W Altcode:
We use Fe XIV 5303 Å green line images obtained by the Large
Angle Spectrometric Coronagraph (LASCO) on board SOHO to search for
variability in the quiescent solar corona in the shortest observable
timescales. The observing program obtained Fe XIV images of a small
area of the inner corona every 2 minutes over a period of 1 hr. We
present results from two executions of this program taken several months
apart. The most obvious variability observed in the two sequences is
in the form of quasi-steady brightening on timescales of at least an
hour. Of particular interest are two compact loops that are observed to
vary significantly during the course of the observations. Superposed on
the long-term brightening in these loops are statistically significant
variations on timescales of about 30 minutes. In both loops, the overall
brightening is greatest at the apparent loop tops, where the intensity
increases by at least 25%. In one loop there appears to be a flow up
one of the legs of the loop. We place these observations in context with
earlier observations of coronal variability, and we discuss the energy
requirements for the observed brightening. Emission measures computed
from Fe XIV intensities measured within the two brightening loops are
over an order of magnitude lower than those typically found for active
regions on the solar disk, which suggests significantly lower average
densities. For one of the loops, we measure densities in the range
n<SUB>e</SUB> = (5.0-7.4) × 10<SUP>8</SUP> cm<SUP>-3</SUP>. Lower
than average densities are expected for the two loops, given that they
reach more than 1 pressure scale height above the solar limb.
---------------------------------------------------------
Title: Missions to the sun II : 22-23 July 1998, San Diego, California
Authors: Korendyke, Clarence M.
1998SPIE.3442.....K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: White-Light Coronal Mass Ejections: A New Perspective from
LASCO
Authors: St. Cyr, O. C.; Howard, R. A.; Simnett, G. M.; Gurman, J. B.;
Plunkett, S. P.; Sheeley, N. R.; Schwenn, R.; Koomen, M. J.; Brueckner,
G. E.; Michels, D. J.; Andrews, M.; Biesecker, D. A.; Cook, J.; Dere,
K. P.; Duffin, R.; Einfalt, E.; Korendyke, C. M.; Lamy, P. L.; Lewis,
D.; Llebaria, A.; Lyons, M.; Moses, J. D.; Moulton, N. E.; Newmark,
J.; Paswaters, S. E.; Podlipnik, B.; Rich, N.; Schenk, K. M.; Socker,
D. G.; Stezelberger, S. T.; Tappin, S. J.; Thompson, B.; Wang, D.
1997ESASP.415..103S Altcode: 1997cpsh.conf..103S
No abstract at ADS
---------------------------------------------------------
Title: Origins of the Slow and the Ubiquitous Fast Solar Wind
Authors: Habbal, S. R.; Woo, R.; Fineschi, S.; O'Neal, R.; Kohl, J.;
Noci, G.; Korendyke, C.
1997ApJ...489L.103H Altcode: 1997astro.ph..9021H
We present in this Letter the first coordinated radio occultation
measurements and ultraviolet observations of the inner corona below
5.5R<SUB>s</SUB>, obtained during the Galileo solar conjunction in
1997 January, to establish the origin of the slow solar wind. Limits
on the flow speed are derived from the Doppler dimming of the
resonantly scattered component of the oxygen 1032 and 1037.6 Å
lines as measured with the ultraviolet coronagraph spectrometer
(UVCS) on the Solar and Heliospheric Observatory (SOHO). White light
images of the corona from the large-angle spectroscopic coronagraph
(LASCO) on SOHO taken simultaneously are used to place the Doppler
radio scintillation and ultraviolet measurements in the context of
coronal structures. These combined observations provide the first
direct confirmation of the view recently proposed by Woo & Martin
that the slow solar wind is associated with the axes, also known as
stalks, of streamers. Furthermore, the ultraviolet observations also
show how the fast solar wind is ubiquitous in the inner corona and
that a velocity shear between the fast and slow solar wind develops
along the streamer stalks.
---------------------------------------------------------
Title: LASCO Observations of Disconnected Magnetic Structures Out
to Beyond 28 Solar Radii During Coronal Mass Ejections
Authors: Simnett, G. M.; Tappin, S. J.; Plunkett, S. P.; Bedford,
D. K.; Eyles, C. J.; St. Cyr, O. C.; Howard, R. A.; Brueckner, G. E.;
Michels, D. J.; Moses, J. D.; Socker, D.; Dere, K. P.; Korendyke,
C. M.; Paswaters, S. E.; Wang, D.; Schwenn, R.; Lamy, P.; Llebaria,
A.; Bout, M. V.
1997SoPh..175..685S Altcode:
Two coronal mass ejections have been well observed by the LASCO
coronagraphs to move out into the interplanetary medium as disconnected
plasmoids. The first, on July 28, 1996, left the Sun above the west
limb around 18:00 UT. As it moved out, a bright V-shaped structure
was visible in the C2 coronagraph which moved into the field-of-view
of C3 and could be observed out to beyond 28 solar radii. The derived
average velocity in the plane of the sky was 110 ± 5 km s<SUP>-1</SUP>
out to 5 solar radii, and above 15 solar radii the velocity was 269
± 10 km s<SUP>-1</SUP>. Thus there is evidence of some acceleration
around 6 solar radii. The second event occurred on November 5, 1996
and left the west limb around 04:00 UT. The event had an average
velocity in the plane of the sky of ∼54 km s<SUP>-1</SUP> below
4 R⊙, and it accelerated rapidly around 5 R⊙ up to 310 ± 10 km
s<SUP>-1</SUP>. In both events the rising plasmoid is connected back
to the Sun by a straight, bright ray, which is probably a signature of
a neutral sheet. In the November event there is evidence for multiple
plasmoid ejections. The acceleration of the plasmoids around a projected
altitude of 5 solar radii is probably a manifestation of the source
surface of the solar wind.
---------------------------------------------------------
Title: First View of the Extended Green-Line Emission Corona At
Solar Activity Minimum Using the Lasco-C1 Coronagraph on SOHO
Authors: Schwenn, R.; Inhester, B.; Plunkett, S. P.; Epple, A.;
Podlipnik, B.; Bedford, D. K.; Eyles, C. J.; Simnett, G. M.; Tappin,
S. J.; Bout, M. V.; Lamy, P. L.; Llebaria, A.; Brueckner, G. E.;
Dere, K. P.; Howard, R. A.; Koomen, M. J.; Korendyke, C. M.; Michels,
D. J.; Moses, J. D.; Moulton, N. E.; Paswaters, S. E.; Socker, D. G.;
St. Cyr, O. C.; Wang, D.
1997SoPh..175..667S Altcode:
The newly developed C1 coronagraph as part of the Large-Angle
Spectroscopic Coronagraph (LASCO) on board the SOHO spacecraft has
been operating since January 29, 1996. We present observations
obtained in the first three months of operation. The green-line
emission corona can be made visible throughout the instrument's full
field of view, i.e., from 1.1 R⊙ out to 3.2 R⊙ (measured from Sun
center). Quantitative evaluations based on calibrations cannot yet be
performed, but some basic signatures show up even now: (1) There are
often bright and apparently closed loop systems centered at latitudes
of 30° to 45° in both hemispheres. Their helmet-like extensions
are bent towards the equatorial plane. Farther out, they merge into
one large equatorial `streamer sheet' clearly discernible out to 32
R⊙. (2) At mid latitudes a more diffuse pattern is usually visible,
well separated from the high-latitude loops and with very pronounced
variability. (3) All high-latitude structures remain stable on time
scales of several days, and no signature of transient disruption of
high-latitude streamers was observed in these early data. (4) Within
the first 4 months of observation, only one single `fast' feature was
observed moving outward at a speed of 70 km s<SUP>-1</SUP> close to
the equator. Faster events may have escaped attention because of data
gaps. (5) The centers of high-latitude loops are usually found at the
positions of magnetic neutral lines in photospheric magnetograms. The
large-scale streamer structure follows the magnetic pattern fairly
precisely. Based on our observations we conclude that the shape
and stability of the heliospheric current sheet at solar activity
minimum are probably due to high-latitude streamers rather than to
the near-equatorial activity belt.
---------------------------------------------------------
Title: The Relationship of Green-Line Transients to White-Light
Coronal Mass Ejections
Authors: Plunkett, S. P.; Brueckner, G. E.; Dere, K. P.; Howard,
R. A.; Koomen, M. J.; Korendyke, C. M.; Michels, D. J.; Moses, J. D.;
Moulton, N. E.; Paswaters, S. E.; St. Cyr, O. C.; Socker, D. G.;
Wang, D.; Simnett, G. M.; Bedford, D. K.; Biesecker, D. A.; Eyles,
C. J.; Tappin, S. J.; Schwenn, R.; Lamy, P. L.; Llebaria, A.
1997SoPh..175..699P Altcode:
We report observations by the Large Angle Spectrometric Coronagraph
(LASCO) on the SOHO spacecraft of three coronal green-line transients
that could be clearly associated with coronal mass ejections (CMEs)
detected in Thomson-scattered white light. Two of these events, with
speeds >25 km s<SUP>-1</SUP>, may be classified as `whip-like'
transients. They are associated with the core of the white-light
CMEs, identified with erupting prominence material, rather than with
the leading edge of the CMEs. The third green-line transient has a
markedly different appearance and is more gradual than the other two,
with a projected outward speed <10 km s<SUP>-1</SUP>. This event
corresponds to the leading edge of a `streamer blowout' type of CME. A
dark void is left behind in the emission-line corona following each of
the fast eruptions. Both fast emission-line transients start off as a
loop structure rising up from close to the solar surface. We suggest
that the driving mechanism for these events may be the emergence of new
bipolar magnetic regions on the surface of the Sun, which destabilize
the ambient corona and cause an eruption. The possible relationship of
these events to recent X-ray observations of CMEs is briefly discussed.
---------------------------------------------------------
Title: MHD Interpretation of LASCO Observations of a Coronal Mass
Ejection as a Disconnected Magnetic Structure
Authors: Wu, S. T.; Guo, W. P.; Andrews, M. D.; Brueckner, G. E.;
Howard, R. A.; Koomen, M. J.; Korendyke, C. M.; Michels, D. J.; Moses,
J. D.; Socker, D. G.; Dere, K. P.; Lamy, P. L.; Llebaria, A.; Bout,
M. V.; Schwenn, R.; Simnett, G. M.; Bedford, D. K.; Eyles, C. J.
1997SoPh..175..719W Altcode:
We present a qualitative and quantitative comparison of a single
coronal mass ejection (CME) as observed by LASCO (July 28-29, 1996)
with the results of a three-dimensional axisymmetric time-dependent
magnetohydrodynamic model of a flux rope interacting with a helmet
streamer. The particular CME considered was selected based on the
appearance of a distinct `tear-drop' shape visible in animations
generated from both the data and the model.
---------------------------------------------------------
Title: EIT and LASCO Observations of the Initiation of a Coronal
Mass Ejection
Authors: Dere, K. P.; Brueckner, G. E.; Howard, R. A.; Koomen, M. J.;
Korendyke, C. M.; Kreplin, R. W.; Michels, D. J.; Moses, J. D.;
Moulton, N. E.; Socker, D. G.; St. Cyr, O. C.; Delaboudinière, J. P.;
Artzner, G. E.; Brunaud, J.; Gabriel, A. H.; Hochedez, J. F.; Millier,
F.; Song, X. Y.; Chauvineau, J. P.; Marioge, J. P.; Defise, J. M.;
Jamar, C.; Rochus, P.; Catura, R. C.; Lemen, J. R.; Gurman, J. B.;
Neupert, W.; Clette, F.; Cugnon, P.; Van Dessel, E. L.; Lamy, P. L.;
Llebaria, A.; Schwenn, R.; Simnett, G. M.
1997SoPh..175..601D Altcode:
We present the first observations of the initiation of a coronal mass
ejection (CME) seen on the disk of the Sun. Observations with the EIT
experiment on SOHO show that the CME began in a small volume and was
initially associated with slow motions of prominence material and a
small brightening at one end of the prominence. Shortly afterward,
the prominence was accelerated to about 100 km s<SUP>-1</SUP> and
was preceded by a bright loop-like structure, which surrounded an
emission void, that traveled out into the corona at a velocity of
200-400 km s<SUP>-1</SUP>. These three components, the prominence,
the dark void, and the bright loops are typical of CMEs when seen at
distance in the corona and here are shown to be present at the earliest
stages of the CME. The event was later observed to traverse the LASCO
coronagraphs fields of view from 1.1 to 30 R⊙. Of particular interest
is the fact that this large-scale event, spanning as much as 70 deg in
latitude, originated in a volume with dimensions of roughly 35" (2.5
x 10<SUP>4</SUP> km). Further, a disturbance that propagated across
the disk and a chain of activity near the limb may also be associated
with this event as well as a considerable degree of activity near the
west limb.
---------------------------------------------------------
Title: Origin and Evolution of Coronal Streamer Structure During
the 1996 Minimum Activity Phase
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Howard, R. A.; Kraemer,
J. R.; Rich, N. B.; Andrews, M. D.; Brueckner, G. E.; Dere, K. P.;
Koomen, M. J.; Korendyke, C. M.; Michels, D. J.; Moses, J. D.;
Paswaters, S. E.; Socker, D. G.; Wang, D.; Lamy, P. L.; Llebaria,
A.; Vibert, D.; Schwenn, R.; Simnett, G. M.
1997ApJ...485..875W Altcode:
We employ coronal extrapolations of solar magnetograph data to interpret
observations of the white-light streamer structure made with the LASCO
coronagraph in 1996. The topological appearance of the streamer belt
during the present minimum activity phase is well described by a model
in which the Thomson-scattering electrons are concentrated around a
single, warped current sheet encircling the Sun. Projection effects
give rise to bright, jet-like structures or spikes whenever the current
sheet is viewed edge-on multiple spikes are seen if the current sheet is
sufficiently wavy. The extreme narrowness of these features in polarized
images indicates that the scattering layer is at most a few degrees
wide. We model the evolution of the streamer belt from 1996 April to
1996 September and show that the effect of photospheric activity on
the streamer belt topology depends not just on the strength of the
erupted magnetic flux, but also on its longitudinal phase relative
to the background field. Using flux transport simulations, we also
demonstrate how the streamer belt would evolve during a prolonged
absence of activity.
---------------------------------------------------------
Title: The Green Line Corona and Its Relation to the Photospheric
Magnetic Field
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Hawley, S. H.; Kraemer,
J. R.; Brueckner, G. E.; Howard, R. A.; Korendyke, C. M.; Michels,
D. J.; Moulton, N. E.; Socker, D. G.; Schwenn, R.
1997ApJ...485..419W Altcode:
Images of the green line corona made with the LASCO C1 coronagraph
on SOHO are analyzed by applying current-free extrapolations to the
observed photospheric field. The Fe XIV λ5303 emission is shown to
be closely related to the underlying photospheric field strength. By
modeling the observed intensity patterns as a function of latitude and
height above the solar limb, we derive an approximate scaling law of the
form n<SUB>foot</SUB> ~ <B<SUB>foot</SUB>><SUP>0.9</SUP>, where
n<SUB>foot</SUB> is the density of the green line-emitting plasma and
<B<SUB>foot</SUB>> is the average field strength at the footprints
of the coronal loop. The observed high-latitude enhancements in the
green line corona are attributed to the poleward concentration of the
large-scale photospheric field. The strongest such enhancements occur
where the high-latitude unipolar fields become reconnected to active
region flux at lower latitudes; the global emission pattern rotates
quasi-rigidly at the rate of the dominant active region complex. The
validity of the current-free approximation is assessed by comparing
the topology of the observed and simulated green line structures.
---------------------------------------------------------
Title: Measurements of Flow Speeds in the Corona Between 2 and 30
R<SUB>⊙</SUB>
Authors: Sheeley, N. R.; Wang, Y. -M.; Hawley, S. H.; Brueckner,
G. E.; Dere, K. P.; Howard, R. A.; Koomen, M. J.; Korendyke, C. M.;
Michels, D. J.; Paswaters, S. E.; Socker, D. G.; St. Cyr, O. C.;
Wang, D.; Lamy, P. L.; Llebaria, A.; Schwenn, R.; Simnett, G. M.;
Plunkett, S.; Biesecker, D. A.
1997ApJ...484..472S Altcode:
Time-lapse sequences of white-light images, obtained during sunspot
minimum conditions in 1996 by the Large Angle Spectrometric Coronagraph
on the Solar and Heliospheric Observatory, give the impression of
a continuous outflow of material in the streamer belt, as if we
were observing Thomson scattering from inhomogeneities in the solar
wind. Pursuing this idea, we have tracked the birth and outflow of
50-100 of the most prominent moving coronal features and find that:
<P />1. They originate about 3-4 R<SUB>⊙</SUB> from Sun center as
radially elongated structures above the cusps of helmet streamers. Their
initial sizes are about 1 R<SUB>⊙</SUB> in the radial direction and
0.1 R<SUB>⊙</SUB> in the transverse direction. <P />2. They move
radially outward, maintaining constant angular spans and increasing
their lengths in rough accord with their speeds, which typically
double from 150 km s<SUP>-1</SUP> near 5 R<SUB>⊙</SUB> to 300 km
s<SUP>-1</SUP> near 25 R<SUB>⊙</SUB>. <P />3. Their individual speed
profiles v(r) cluster around a nearly parabolic path characterized
by a constant acceleration of about 4 m s<SUP>-2</SUP> through most
of the 30 R<SUB>⊙</SUB> field of view. This profile is consistent
with an isothermal solar wind expansion at a temperature of about
1.1 MK and a sonic point near 5 R<SUB>⊙</SUB>. <P />Based on their
relatively small initial sizes, low intensities, radial motions, slow
but increasing speeds, and location in the streamer belt, we conclude
that these moving features are passively tracing the outflow of the
slow solar wind.
---------------------------------------------------------
Title: Using LASCO Observations to Infer Solar Wind Flow Near the Sun
Authors: Sheeley, N. R., Jr.; Brueckner, G. E.; Dere, K. P.; Howard,
R. A.; Korendyke, C. M.; Michels, D. J.; Socker, D. G.; Koomen, M. J.;
Paswaters, S. E.; Wang, D.; Lamy, P. L.; Llebaria, A.; Schwenn, R.;
St Cyr, O. C.; Simnett, G. M.; Plunkett, S.; Biesecker, D. A.
1997SPD....28.0301S Altcode: 1997BAAS...29..907S
We have continued to track individual coronal features as they become
detached from helmet streamers and move outward from the Sun. The
composite speed profile for 50-100 features has a parabolic shape
with a constant acceleration of about 4 m/s(2) over the 2-30 R field
of view. This well-determined speed profile contrasts strongly with
the nearly uniform scatterplot obtained for about 50 nominal coronal
mass ejections (CMEs), and suggests that these detached bits of coronal
“debris” are passively tracing the speed of the slow solar wind. We
have also begun the more difficult task of tracking outflow along
polar plumes and will summarize these results as of June 1997.
---------------------------------------------------------
Title: Search for Velocity Signatures of Energy Release in Fine
Scale Coronal Features
Authors: Cook, J. W.; Socker, D. G.; Korendyke, C. M.; Howard, R. A.;
Karovska, M.
1997SPD....28.0119C Altcode: 1997BAAS...29..882C
The Large Angle Spectrometric Coronagraph (LASCO) on the SOHO satellite
consists of three individual coronagraphs with nested fields of
view. The innermost C1 coronagraph observes the solar corona from 1.1
to 3.0 R_⊙, and contains a Fabry Perot interferometer which can image
the corona in the 1.8 million K Fe XIV emission line at 5303 Angstroms
with 0.7 Angstroms resolution. We designed an observing program with
reduced spatial coverage and reduced profile coverage at only three
wavelengths (line center and the half power points of the thermal plus
instrumental profile) in order to increase the observing cadence. From
these observations we can construct maps of the observed field in
integrated line intensity, doppler velocity shift, and nonthermal
broadening. We can thus search for signatures of coronal heating such
as transient brightenings, bulk velocity flows, or nonthermal turbulent
line broadening at spatial scales down to 11 arc sec (two CCD pixels),
with temporal resolution of 4 minutes. We have run this program several
times so far, and will report on early results.
---------------------------------------------------------
Title: Dynamical Evolution of a Coronal Mass Ejection (CME) to
Magnetic Cloud: A Preliminary Analysis of the January 6-10, 1997
CME Observed by LASCO/SOHO
Authors: Wu, S. T.; Guo, W. P.; Michels, D. J.; Andrews, M. D.;
Brueckner, G. E.; Howard, R. A.; Koomen, M. J.; Korendyke, C. M.;
Moses, J. D.; Socker, D. G.; Dere, K. P.; Bougeret, Jean-Louis; Lamy,
P. L.; Schwenn, R.; Simnett, G. M.
1997ESASP.404..739W Altcode: 1997cswn.conf..739W
No abstract at ADS
---------------------------------------------------------
Title: EIT and LASCO Observations of the Initiation of a Coronal
Mass Ejection
Authors: Dere, K. P.; Brueckner, G. E.; Howard, R. A.; Koomen, M. J.;
Korendyke, C. M.; Michels, D. J.; Moses, J. D.; Moulton, N. E.; Socker,
D. G.; Delaboudiniere, J. P.; Hochedez, J. F.; Lamy, P. L.; Schwenn,
R.; Simnett, G. M.; Defise, J. M.; Catura, R. C.
1997IAUJD..19E..18D Altcode:
We present the first observations of the initiation of a corona mass
ejection (CME) seen on the disk of the Sun. Observations with the EIT
and LASCO experiments on SOHO show that the CME starts in a small volume
and is associated with slow motions of prominence material. At about
the same time, a shock wave is created that travels out into the corona
at a velocity of 400 km s^{-1} ahead of an eruptive prominence. This
shock wave is clearly the event that is later seen as a classical CME
when observed in the coronagraph above 1.5 solar radii. Although the
CME clearly starts in a small region, a chain of activity near the
limb may also be associated with this event.
---------------------------------------------------------
Title: The quiescent corona and slow solar wind
Authors: Noci, G.; Kohl, J. L.; Antonucci, E.; Tondello, G.; Huber,
M. C. E.; Fineschi, S.; Gardner, L. D.; Korendyke, C. M.; Nicolosi,
P.; Romoli, M.; Spadaro, D.; Maccari, L.; Raymond, J. C.; Siegmund,
O. H. W.; Benna, C.; Ciaravella, A.; Giordano, S.; Michels, J.;
Modigliani, A.; Naletto, G.; Panasyuk, A.; Pernechele, C.; Poletto,
G.; Smith, P. L.; Strachan, L.
1997ESASP.404...75N Altcode: 1997cswn.conf...75N; 1997soho....5...75N
No abstract at ADS
---------------------------------------------------------
Title: Enhancing the Spatial Resolution of Solar Coronagraph
Observations Using Dynamic Imaging
Authors: Zaccheo, T. S.; Karovska, M.; Cook, J. W.; Howard, R. A.;
Brueckner, G. E.; Korendyke, C. M.; Schwenn, R.
1996ApJ...471.1058Z Altcode:
The Large Angle Spectrometric Coronagraph (LASCO) Cl coronagraph on
board the Solar and Heliospheric Observatory (SOHO) is designed to
image the corona from 1.1 to 3.0 R<SUB>sun</SUB>. The resolution of
C1 is defined by the size of its CCD pixels, which correspond to 5".6,
and not by the diffraction limit of the optical system, which may be as
small as 3". The resolution of Cl can be improved using the technique of
"dynamic imaging" the process of acquiring successive images of the same
scene using sub- pixel displacements of the steerable primary mirror. We
developed a technique we call the fractional pixel restoration (F PR)
algorithm that utilizes these observations to construct an image with
improved resolution. Simulations were used to test this algorithm and
to explore its limitations. We also applied the direct co-addition
and FPR algorithms to laboratory preffight images of a wire mesh
grid. These results show that the resolution of the C1 coronagraph can
be significantly enhanced, even in the presence of noise and modest
differences between successive images. In some cases, the results can
even reach the diffraction limit of the telescope.
---------------------------------------------------------
Title: LASCO spectrometric Lyot coronagraph tunable passband filter
Authors: Socker, Dennis G.; Brueckner, Guenter E.; Korendyke, Clarence
M.; Lilley, D. N.; Steenson, James H.; Kohn, Preston M.; Lyons, Gail
M.; Owens, Michael L.; Moulton, Norman E.; Moye, Robert W.; Schwenn,
Rainer; Hemmerich, P.
1996SPIE.2804..126S Altcode:
Spectrometric and spectropolarimetric aspects of the Lyot coronagraph
flown aboard the ESA/NASA SOlar Heliospheric Observatory (SOHO) are
presented. The coronagraph is one of the three channels comprising
the LASCO coronagraph and the only channel with spectroradiometric
capabilities. Among the primary science objectives assigned to the
Lyot coronagraph are the determination of the mechanisms responsible
for the acceleration of the solar wind and the heating of the
corona. Spectrometric and spectropolarimetric coronal observations
made with the Lyot coronagraph are used in support of these and
other objectives. We describe the Lyot instrument design from the
imaging coronal spectrometer perspective. The rationale for use
of a tunable Fabry-Perot interferometer as the spectral resolving
element is outlined. The relationships between spectral resolving
power, interferometer diameter, telescope entrance stop diameter and
coronal field of view as it applies to LASCO is reviewed. Performance
requirements imposed on the interferometer by the coronal source and the
science objectives are described. The optical, mechanical, electronic
and semi-automated control designs as well as the interferometer
modes of operation are summarized. The actual flight model Fabry-Perot
interferometer performance allows the instrument to operate with high
luminosity and with finesse values high enough to provide approximately
optimal passband widths and reasonable tunable ranges about useful
spectral features. We conclude with some early results indicative of
the flight performance of the instrument.
---------------------------------------------------------
Title: STEREO: a solar terrestrial event observer mission concept
Authors: Socker, Dennis G.; Antiochos, S. K.; Brueckner, Guenter E.;
Cook, John W.; Dere, Kenneth P.; Howard, Russell A.; Karpen, J. T.;
Klimchuk, J. A.; Korendyke, Clarence M.; Michels, Donald J.; Moses,
J. Daniel; Prinz, Dianne K.; Sheely, N. R.; Wu, Shi T.; Buffington,
Andrew; Jackson, Bernard V.; Labonte, Barry; Lamy, Philippe L.;
Rosenbauer, H.; Schwenn, Rainer; Burlaga, L.; Davila, Joseph M.; Davis,
John M.; Goldstein, Barry; Harris, H.; Liewer, Paulett C.; Neugebauer,
Marcia; Hildner, E.; Pizzo, Victor J.; Moulton, Norman E.; Linker,
J. A.; Mikic, Z.
1996SPIE.2804...50S Altcode:
A STEREO mission concept requiring only a single new spacecraft has been
proposed. The mission would place the new spacecraft in a heliocentric
orbit and well off the Sun- Earth line, where it can simultaneously view
both the solar source of heliospheric disturbances and their propagation
through the heliosphere all the way to the earth. Joint observations,
utilizing the new spacecraft and existing solar spacecraft in earth
orbit or L1 orbit would provide a stereographic data set. The new
and unique aspect of this mission lies in the vantage point of the
new spacecraft, which is far enough from Sun-Earth line to allow an
entirely new way of studying the structure of the solar corona, the
heliosphere and solar-terrestrial interactions. The mission science
objectives have been selected to take maximum advantage of this new
vantage point. They fall into two classes: those possible with the
new spacecraft alone and those possible with joint measurements using
the new and existing spacecraft. The instrument complement on the new
spacecraft supporting the mission science objectives includes a soft
x-ray imager, a coronagraph and a sun-earth imager. Telemetry rate
appears to be the main performance determinant. The spacecraft could
be launched with the new Med-Lite system.
---------------------------------------------------------
Title: Next-generation EUV imaging spectrometer for solar flare
observations
Authors: Moses, J. Daniel; Brueckner, Guenter E.; Dere, Kenneth P.;
Korendyke, Clarence M.; Moulton, Norman E.; Prinz, Dianne K.; Seely,
John F.; Socker, Dennis G.; Bruner, Marilyn E.; Lemen, James R.
1996SPIE.2804..260M Altcode:
The Naval Research Laboratory Skylab SO82A slitless spectrograph
provided solar flare observations that have never been equaled
in diagnostic capabilities for interpreting thermal flare
physics. Improvements in detector technology, optics and optical
coating technology, and almost two decades of analysis of SO82A data
can be combined with the basic concept of an EUV objective grating
spectrograph to build an instrument to address many of the remaining
mysteries of solar flares. This next generation instrument incorporates
two sets of two identical, orthogonally mounted slitless spectrographic
Cassegrain telescopes. Each telescope consists of a multilayer coated,
Wadsworth mount objective grating and multilayer coated spherical
secondary mirror; a backside illuminated CCD detector is installed
at the focal plane. The orthogonal mounting changes the dispersion
direction by 90 degrees on the disk image; processing on the two
resulting images allows recovery of the undispersed disk image and
spectral line profiles. The resulting instrument will obtain high time
cadence, spectrally-dispersed images with improved spatial resolution,
dynamic range, signal-to-noise ratio, and velocity discrimination.
---------------------------------------------------------
Title: LASCO Observations of the 03Feb96 Streamer Blow-out
Authors: Andrews, M. D.; Korendyke, C. M.; Koomen, M. J.; Brueckner,
G. E.; Cook, J. W.; Dere, K. P.; Howard, R. A.; Michels, D. J.; Moses,
J. D.; Morrill, J. S.; Moulton, N. E.; Paswaters, S. E.; Socker, D. G.;
St. Cyr, O. C. St.; Wang, D.; Lamy, P. L.; Llebaria, A.; Bout, M. V.;
Schwenn, R.; Podlipnik, B.; Bedford, D. K.; Biesecker, D. A.; Eyles,
C. J.; Plunkett, S.; Simnett, G. M.
1996AAS...188.3716A Altcode: 1996BAAS...28..880A
The C2 and C3 telescopes on the Large Angle Spectrometric Coronograph
(LASCO) have recorded images of a Streamer Blow-out which occured
on 03Feb96. We will present a series of images produces by combining
data from the 2 coronographs. These images show a rapid evolution of
the coronal streamer belt over projected distances of 2 to 20 solar
radii. The streamer belt shows a dramatic brightening, which is seen to
propagate outward. A bubble-like structure is seen to move away from
the Sun and expand. At the end of this event, the equatorial corona
is significantly less bright than prior to the event.
---------------------------------------------------------
Title: LASCO Observations of the Solar Corona to 32 R<SUB>sun</SUB>
Authors: Cook, J. W.; Koomen, M. J.; Korendyke, C. M.; Brueckner,
G. E.; Dere, K. P.; Howard, R. A.; Michels, D. J.; Morrill, J. S.;
Moses, J. D.; Socker, D. G.; Paswaters, S. E.; Wang, D.; Moulton,
N. E.; Cyr, O. C. St.; Andrews, M. D.; Schwenn, R.; Podlipnik, B.;
Lamy, P. L.; Llebaria, A.; Bout, M. V.; Simnett, G. M.; Bedford,
D. K.; Eyles, C. J.; Plunkett, S.; Biesecker, D. A.
1996AAS...188.3717C Altcode: 1996BAAS...28..880C
The Large Angle Spectrometric Coronagraph (LASCO) was launched on
board the SOHO satellite on 2 December 1995. The C3 externally-occulted
coronagraph of LASCO observes the solar corona over a field from 3.7-32
R_ ⊙, using a 1024x1024 CCD detector with a pixel size corresponding
to 56 arc sec. Observations can be made using color filters ranging
from the blue (420-520 nm) to the near-IR (860-1050 nm), and through
polarizing filters. We report on early observations of the solar corona
out to 32 R<SUB>sun</SUB>.
---------------------------------------------------------
Title: Preliminary Photometric Calibration of LASCO C3 Coronagraph
Images using Pre-Flight Laboratory Images of Standard Sources and
In-Flight Images of Standard Stars
Authors: Korendyke, C. M.; Koomen, M. J.; Andrews, M. D.; Brueckner,
G. E.; Cook, J. W.; Dere, K. P.; Howard, R. A.; Michels, D. J.;
Moses, J. D.; Morrill, J. S.; Moulton, N. E.; Paswaters, S. E.;
Socker, D. G.; St. Cyr, O. C.; Wang, D.; Lamy, P. L.; Llebaria, A.;
Bout, M. V.; Schwenn, R.; Podlipnik, B.; Bedford, D. K.; Biesecker,
D. A.; Eyles, C. J.; Plunkett, S.; Simnett, G. M.
1996AAS...188.3621K Altcode: 1996BAAS...28..876K
The C3 coronagraph is a wide field (+/-8.0 degrees), externally
occulted, white light coronagraph. The instrument is one of three
coronagraphs comprising the Large Angle Spectrometric COronagraph
(LASCO) experiment mounted on the Solar Heliospheric Observatory
satellite. The satellite was launched on Dec. 2, 1996; C3 observations
began in early Jan. 1997. The coronagraph optical train includes a set
of five broadband color filters mounted in a wheel. Prior to flight,
an image was obtained through each color filter of a well characterized,
rear-illuminated, opal glass diffusing screen. The C3 in-flight images,
in addition to the coronal structures, also contain several hundred
bright stars. We present a comparison of the photometric calibration
derived from standard stars with the laboratory measurements. The
resulting calibration is then used to examine color variations in the
white light corona over the field of view. The LASCO experiment was
developed by a scientific consortium of members from NRL (USA), MPAe
(Germany), LAS (France) and U. Birmingham (United Kingdom).
---------------------------------------------------------
Title: Intercalibration and Co-Registration of the LASCO, UVCS and
SUMER instruments on SOHO
Authors: Michels, J.; Kohl, J. L.; Noci, G.; Antonucci, E.; Tondello,
G.; Huber, M. C. E.; Curdt, W.; Hollandt, J.; Lemaire, P.; Schuhle,
U.; Wilhelm, K.; Korendyke, C.; Moran, T.; Raymond, J. C.; Romoli,
M.; Benna, C.; Ciaravella, A.; Fineschi, S.; Gardner, L. D.; Giordano,
S.; Naletto, G.; Nicolosi, P.; Siegmund, O. H. W.; Spadaro, D.; Smith,
P. L.; Strachan, L.
1996AAS...188.3706M Altcode: 1996BAAS...28..878M
Joint observations of equatorial streamers by three SOHO instruments
have been used for radiometric intercalibration, co-registration and
other spectroscopic comparisons. The results are used to track the
stability of the radiometric calibrations of the Ultraviolet Coronagraph
Spectrometer (UVCS) and the Solar Ultraviolet Measurements of Emitted
Radiation (SUMER) experiment at overlapping wavelenghs. Observations
of equatorial streamers at heliocentric heights from 1.25 to 1.5
R_⊙ are used for the intercalibrations. The results are compared to
pre-launch laboratory calibrations and to observations of stars. The
first stellar observation was for 38 AQI. These UV observations are
compared to coronal green line (Fe XIV) observations obtained with the
Large Angle Spectrometric Coronagraph (LASCO) C1 coronagraph obtained
in the same time frame. Intercomparisons of spectral line profiles
among LASCO, SUMER, and UVCS are also planned. The LASCO research is
supported by NASA Grant NDPR S92835D; the UVCS research is supported by
NASA Contract NAS5-31250 to the Smithsonian Astrophysical Observatory,
by the Italian Space Agency and by Switzerland, and SUMER is financially
supported by BMFT/DARA, CNES, NASA and PRODEX (Swiss Contribution).
---------------------------------------------------------
Title: Observations of the comet Hyakutake by the LASCO coronagraph
on the SOHO satellite.
Authors: Andrews, M. D.; Paswaters, S. E.; Brueckner, G. E.; Korendyke,
C. M.; Dere, K. P.; Howard, R. A.; Michels, D. J.; Moses, J. D.;
Morril, J. S.; Moulton, N. E.; Socker, D. G.; St. Cyr, O. C.; Wang,
D.; Lamy, P. L.; Llebaria, A.; Bout, M. V.; Schwenn, R.; Podlipnik,
B.; Bedford, D. K.; Biesecker, D. A.; Eyles, C. J.; Plunket, S.;
Simnet, G. M.
1996BAAS...28.1195A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Large Angle Spectroscopic Coronagraph (LASCO)
Authors: Brueckner, G. E.; Howard, R. A.; Koomen, M. J.; Korendyke,
C. M.; Michels, D. J.; Moses, J. D.; Socker, D. G.; Dere, K. P.;
Lamy, P. L.; Llebaria, A.; Bout, M. V.; Schwenn, R.; Simnett, G. M.;
Bedford, D. K.; Eyles, C. J.
1995SoPh..162..357B Altcode:
The Large Angle Spectroscopic Coronagraph (LASCO) is a three
coronagraph package which has been jointly developed for the Solar
and Heliospheric Observatory (SOHO) mission by the Naval Research
Laboratory (USA), the Laboratoire d'Astronomie Spatiale (France),
the Max-Planck-Institut für Aeronomie (Germany), and the University
of Birmingham (UK). LASCO comprises three coronagraphs, C1, C2, and C3,
that together image the solar corona from 1.1 to 30 R<SUB>⊙</SUB> (C1:
1.1 - 3 R<SUB>⊙</SUB>, C2: 1.5 - 6 R<SUB>⊙</SUB>, and C3: 3.7 - 30
R<SUB>⊙</SUB>). The C1 coronagraph is a newly developed mirror version
of the classic internally-occulted Lyot coronagraph, while the C2 and
C3 coronagraphs are externally occulted instruments. High-resolution
imaging spectroscopy of the corona from 1.1 to 3 R<SUB>⊙</SUB> can
be performed with the Fabry-Perot interferometer in C1. High-volume
memories and a high-speed microprocessor enable extensive on-board image
processing. Image compression by a factor of about 10 will result in
the transmission of 10 full images per hour.
---------------------------------------------------------
Title: Ultraviolet Observations of the Structure and Dynamics of an
Active Region at the Limb
Authors: Korendyke, C. M.; Dere, K. P.; Socker, D. G.; Brueckner,
G. E.; Schmieder, B.
1995ApJ...443..869K Altcode:
The structure and dynamics of active region NOAA 7260 at the limb have
been studied using ultraviolet spectra and spectroheliograms obtained
during the eighth rocket flight of the Naval Research Laboratory's
High Resolution Telescope an Spectrograph (HRTS). The instrument
configuration included a narrow-bandpass spectroheliograph to observe
the Sun in the lines of C IV lambda 550 and a tandem-Wadsworth mount
spectrograph to record the profiles of chromospheric transition
region and coronal lines in the 1850-2670 A region. The combination
of high spatial resolution and high spectral purity C IV slit jaw
images with ultraviolet emission-line spectra corresponding allows
examination of a variety of active region phenomena. A time series
of spectroheliograms shows large-scale loop systems composed of
fine-scale threads with some extending up to 100 Mm above the
limb. The proper motion of several supersonic features, including
a surge were measured. The accelerated plasmas appear in several
different geometries and environments. Spectrograph exposures were
taken with the slit positioned at a range of altitudes above the limb
and provide a direct comparison between coronal, transition region
and chromospheric emission line profiles. The spectral profiles of
chromospheric and transition region emission lines show line-of-sight
velocities up to 70 km/s. These lower temperature, emission-line spectra
show small-scale spatial and velocity variations which are correlated
with the threadlike structures seen in C IV. Coronal lines of Fe XII
show much lower velocities and no fine structure.
---------------------------------------------------------
Title: Spectrometric and spectropolarimetric observation of the
solar corona with the LASCO/SOHO Lyot coronagraph
Authors: Socker, Dennis G.; Brueckner, Guenther E.; Korendyke,
Clarence M.; Schwenn, Reinhard
1994SPIE.2283...53S Altcode:
A spectrometric and spectropolarimetric visible light Lyot coronagraph
are scheduled for launch in 1995 on the ESA/NASA Solar Heliospheric
Observatory (SOHO) mission. The Lyot coronagraph is one of three
coronagraph optical trains contained in the NASA sponsored large
angle spectrometric coronagraph (LASCO) which will be used to study
the emission line, electron, and dust components of the solar corona
within a 30 solar diameter field of view. This talk focuses on the
spectrometric and polarimetric capabilities of the Lyot optical train
which covers the inner solar corona from 1.1 - 3.0 solar radii.
---------------------------------------------------------
Title: Combined HRTS-8 Sounding Rocket Observations and YOHKOH Soft
X-ray Observations of NOAA Active Region 7260 at the Solar Limb
Authors: Korendyke, C. M.; Dere, K. P.; Brueckner, G. E.; Waljeski,
K.; Lemen, J. R.
1994kofu.symp..293K Altcode:
On 24 August 1992, the Naval Research Laboratory (NRL) High Resolution
Telescope and Spectrograph (HRTS) was launched aboard a Black Brant
sounding rocket from White Sands, New Mexico. During the flight, the
instrument recorded a unique set of near ultraviolet slit spectra and
1550 A spectroheliograms of an active region at the solar limb. An
extensive set of observations of this region were obtained with the
Yohkoh Soft X-ray Telescope (SXT) near the time of the flight. The C IV
spectroheliograms obtained during this flight are some of the highest
resolution images of the solar transition region ever obtained. The
spectra and spectroheliograms dramatically demonstrate the fundamental
difference between coronal and chromospheric/transition-region plasmas
at 700 km spatial scales. The cooler plasmas exhibit a great deal of
dynamic, fine scale structure with significant flows or proper motion
particularly in the transition zone loops. The coronal emission lines
in the spectra! are relatively uniform and quiescent. The Yohkoh data
during the period before and after the flight show a set of diffuse
high temperature coronal loops with only minimal correspondence to
the structures visible in the C IV spectroheliograms.
---------------------------------------------------------
Title: Optical design of a near-ultraviolet coronagraph for a sounding
rocket platform
Authors: Korendyke, Clarence M.; Prinz, Dianne K.; Socker, Dennis G.
1994OptEn..33..479K Altcode:
The near-UV (190 to 270 nm) coronal emission lines present a unique
opportunity to observe heliospheric plasmas between one and two solar
radii. The near-UV coronagraph was specifically designed to obtain
observations in these lines from a sounding rocket platform. The
design demonstrates that high-resolution, two-dimensional coronal
observations in the near-UV are readily achievable within the practical
constraints of a sounding rocket. The near- UV coronagraph consists of
a reflective, coronagraph telescope followed by an imaging channeled
spectrograph. The telescope includes a Lyot stop and an occulter to
minimize instrumentally scattered disk radiation. The choice of a
mirror objective gives rise to a compact, achromatic telescope with
excellent off-axis rejection and good imaging properties. The focal
plane package combines a Fabry-Perot interferometer with a tandem
Wadsworth spectrograph to produce a channeled spectrum consisting
of a series of two-dimensional (25 X 500 arcsec), narrow-bandpass
(approximately 0.1 angstroms) images at the instrument focal plane. The
instrument will produce a number of high-spatial-resolution (<
1 arcsec) coronal images in a single flight.
---------------------------------------------------------
Title: Status of the LASCO Instrument Development Program
Authors: Moses, D.; Brueckner, G. E.; Howard, R. A.; Koomen, M. J.;
Korendyke, C. M.; Michels, D. J.; Socker, D. G.; Lamy, P.; Schwenn,
R.; Simnett, G. M.
1993BAAS...25.1192M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A Description of the HRTS-8 Instrument Configuration
Authors: Korendyke, C. M.; Dere, K. P.; Brueckner, G. E.; Socker, D. G.
1993BAAS...25.1182K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: HRTS Untraviolet Observations of the Chromosphere Transition
Region and Corona of a Solar Active Region
Authors: Dere, K. P.; Korendyke, C. M.; Brueckner, G. E.
1993BAAS...25.1182D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Description and Performance of the Recently Completed Naval
Research Laboratory Solar Instrument Test Facility
Authors: Korendyke, C. M.; Brueckner, G. E.; Koomen, M. J.; Michels,
D. J.
1993BAAS...25.1191K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Large Angle Spectroscopic Coronagraph (LASCO): visible
light coronal imaging and spectroscopy.
Authors: Brueckner, G. E.; Howard, R. A.; Koomen, M. J.; Korendyke,
C.; Michels, D. J.; Socker, D. G.; Lamy, P.; Llebaria, A.; Maucherat,
J.; Schwenn, R.; Simnett, G. M.; Bedford, D. K.; Eyles, C. J.
1992ESASP.348...27B Altcode: 1992cscl.work...27B
The Large Angle Spectroscopic Coronagraph (LASCO) is a triple
coronagraph being jointly developed for the SOlar and Heliospheric
Observatory (SOHO) mission by the Naval Research Laboratory (USA),
the Laboratoire d'Astronomie Spatiale (France), the Max Planck
Institut für Aeronomie (Germany), and the University of Birmingham
(UK). LASCO comprises three nested coronagraphs (C1, C2, and C3)
that image the solar corona from 1.1 R<SUB><SUB>sun</SUB></SUB> to
30 R<SUB><SUB>sun</SUB></SUB>.
---------------------------------------------------------
Title: LASCO - Large Angle Spectrometric Coronagraph for SOHO
Authors: Howard, R. A.; Brueckner, G. E.; Dere, K. P.; Korendyke,
C. M.; Koomen, M. J.; Michels, D. J.; Moses, D.; Socker, D. G.;
Schwenn, R.; Inhester, B.; Lamy, P.; Maucherat, A.; Simnett, G. M.;
Eyles, C.
1992AAS...180.3307H Altcode: 1992BAAS...24..781H
No abstract at ADS
---------------------------------------------------------
Title: The Optical Design of the Spectrocoronagraph: an Ultraviolet
Coronagraph Payload for a Sounding Rocket Platform
Authors: Korendyke, Clarence Marinus
1992PhDT........14K Altcode:
The spectrocoronagraph was specifically designed to observe the solar
corona utilizing the relatively unexplored near-UV emission lines
present above the solar limb. These lines were first observed by the
Naval Research Laboratory Skylab spectrograph and are relatively bright
with respect to the solar disk. They contain a number of useful plasma
temperature and density diagnostics. The instrument allows a large
number of high spatial resolution (<1 arc-second), narrow bandwidth
(~0.1A), two dimensional coronal images in these emission lines to be
obtained during a single sounding rocket flight. These observations will
yield valuable information on the dominant physical processes present
in the inner corona. The spectrocoronagraph consists of a low stray
light telescope followed by an imaging spectrograph. The telescope
and spectrograph designs incorporate new features to enhance their
performance. The coronagraph telescope design includes a Lyot stop and
an occulter to reduce instrument stray light levels. The nontraditional
choice of a mirror objective allows a compact design with superb solar
rejection, no chromatic aberration and excellent imaging properties. The
focal plane package utilizes a Fabry-Perot (FP) interferometer in
series with a grating spectrograph to produce a channelled spectrum
consisting of a series of two dimensional, narrow bandwidth images at
the instrument focal plane. All significant optical performance issues
have been examined and resolved. The optical performance of near-UV FP
interferometer coatings was investigated and found to be sufficient for
this application. Measurements of visible and near-UV scattered light
from two superpolished mirrors were obtained. The visible measurements
showed that the near specular scattered light from these mirrors was
equivalent to or better than scattered light from coronagraph quality
lenses and mirrors described in the literature. The scattered disk
radiation originating at the mirror objective was predicted from the
near-UV measurements and compared favorably with coronal intensites
at the focal plane.
---------------------------------------------------------
Title: The Prime Energy Release of a Solar Flare
Authors: Brueckner, G. E.; Moses, D.; Cook, J. W.; Dere, K. P.;
Korendyke, C. M.; Socker, D. G.; Bartoe, J. -D. F.
1991BAAS...23.1026B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Flaring Active Region Structures in the Corona, Transition
Region, and Lower Atmosphere Observed in the SAROC
Authors: Moses, D.; Brueckner, G. E.; Cook, J. W.; Dere, K. P.;
Korendyke, C. M.; Socker, D. G.; Bartoe, J. -D. F.
1991BAAS...23.1026M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The OSL/HRTS VUV CCD Development Program
Authors: Socker, D. G.; Marchywka, M.; Korendyke, C.
1991BAAS...23.1037S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The HRTS/OSL Vacuum Ultraviolet CCD Development Program
Authors: Socker, D. G.; Dere, K. P.; Korendyke, C. M.
1990BAAS...22..889S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Imaging channeled spectrograph: a high resolution spectrometer
providing multiple simultaneous 2-D monochromatic images over a
large spectral range
Authors: Korendyke, Clarence M.
1988ApOpt..27.4187K Altcode:
An imaging channeled spectrograph (ICS) consists of a Fabry-Perot
bandpass filter followed by a wide-slit imaging grating
spectrograph. This unique configuration combines the two-dimensional
monochromatic imaging of a Fabry-Perot system with the high resolution
and comprehensive wavelength coverage of a grating spectrograph. The
ICS produces a series of simultaneous, high-resolution, nonoverlapping,
two-dimensional monochromatic images uniformly distributed over a
large spectral range. This paper describes the ICS optical properties
in general and calculates the optical performance of an ICS designed
for the proposed NRL spectrocoronagraph.
---------------------------------------------------------
Title: Optical Properties of a near-UV Solar Imaging Channelled
Spectrograph
Authors: Korendyke, C. M.; Socker, D. G.
1988BAAS...20..990K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Stray Light Measurements of Reflecting Coronagraph Mirrors
at lambda = 6328 Å
Authors: Socker, D. G.; Korendyke, C. M.
1988BAAS...20..990S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Imaging and spectral performance of Fabry-Perot interferometers
at 2288 Å.
Authors: Socker, D. G.; Korendyke, C. M.
1986BAAS...18..851S Altcode:
No abstract at ADS