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Author name code: artzner
ADS astronomy entries on 2022-09-14
author:"Artzner, Guy"
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Title: Coronographie interferéntielle pour la mission spatuale
DARWIN: expérience de validation en laboratoire
Authors: Ollivier, Marc; Mariotti, Jean-Marie; Brunaud, Jacqueline;
Michel, Guy; Bouchareine, Patrick; Léger, Alain; Artzner, Guy; Malbet,
Fabien; Puget, Pascal; Coudé du Foresto, Vincent; Mennesson, Bertrand
2018SPIE10570E..0PO Altcode:
This paper, "Coronographie interferéntielle pour la mission spatuale
DARWIN: expérience de validation en laboratoire," was presented as
part of International Conference on Space Optics—ICSO 1997, held in
Toulouse, France.
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Title: Time Evolution of the Altitude of an Observed Coronal Wave
Authors: Delannée, C.; Artzner, G.; Schmieder, B.; Parenti, S.
2014SoPh..289.2565D Altcode: 2014SoPh..tmp...49D; 2013arXiv1310.5623D
The nature of coronal wave fronts is intensely debated. They are
observed in several wavelength bands and are frequently interpreted as
magnetosonic waves propagating in the lower solar atmosphere. However,
they can also be attributed to the line-of-sight projection of the
edges of coronal mass ejections. Therefore, estimating the altitude of
these features is crucial for deciding in favor of one of these two
interpretations. We took advantage of a set of observations obtained
from two different view directions by the EUVI instrument onboard
the STEREO mission on 7 December 2007 to derive the time evolution of
the altitude of a coronal wave front. We developed a new technique to
compute the altitude of the coronal wave and found that the altitude
increased during the initial 5 min and then slightly decreased back to
the low corona. We interpret the evolution of the altitude as follows:
the increase in the altitude of the wave front is linked to the rise
of a bubble-like structure depending on whether it is a magnetosonic
wave front or a CME in the initial phase. During the second phase, the
observed brightness of the wave front was mixed with the brightening
of the underlying magnetic structures as the emission from the wave
front faded because the plasma became diluted with altitude.
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Title: A Multi-spacecraft View of a Giant Filament Eruption during
2009 September 26/27
Authors: Gosain, Sanjay; Schmieder, Brigitte; Artzner, Guy; Bogachev,
Sergei; Török, Tibor
2012ApJ...761...25G Altcode: 2012arXiv1210.6686G
We analyze multi-spacecraft observations of a giant filament eruption
that occurred during 2009 September 26 and 27. The filament eruption was
associated with a relatively slow coronal mass ejection. The filament
consisted of a large and a small part, and both parts erupted nearly
simultaneously. Here we focus on the eruption associated with the
larger part of the filament. The STEREO satellites were separated
by about 117° during this event, so we additionally used SoHO/EIT
and CORONAS/TESIS observations as a third eye (Earth view) to aid our
measurements. We measure the plane-of-sky trajectory of the filament as
seen from STEREO-A and TESIS viewpoints. Using a simple trigonometric
relation, we then use these measurements to estimate the true direction
of propagation of the filament which allows us to derive the true
R/R <SUB>⊙</SUB>-time profile of the filament apex. Furthermore, we
develop a new tomographic method that can potentially provide a more
robust three-dimensional (3D) reconstruction by exploiting multiple
simultaneous views. We apply this method also to investigate the 3D
evolution of the top part of filament. We expect this method to be
useful when SDO and STEREO observations are combined. We then analyze
the kinematics of the eruptive filament during its rapid acceleration
phase by fitting different functional forms to the height-time
data derived from the two methods. We find that for both methods an
exponential function fits the rise profile of the filament slightly
better than parabolic or cubic functions. Finally, we confront these
results with the predictions of theoretical eruption models.
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Title: A Technique for Removing Background Features in SECCHI -
EUVI He II 304 Å Filtergrams: Application to the Filament Eruption
of 22 May 2008
Authors: Artzner, G.; Gosain, S.; Schmieder, B.
2010SoPh..262..437A Altcode: 2010SoPh..tmp...41A; 2010SoPh..tmp...53A; 2010arXiv1001.4884A
The STEREO mission has been providing a stereoscopic view of filament
eruptions in the EUV. The clearest view during a filament eruption
is seen in He II 304 Å observations. One of the main problems in
visualizing filament dynamics in He II 304 Å is the strong background
contrast due to surface features. We present a technique that removes
background features and leaves behind only the filamentary structure, as
seen by STEREO-A and -B. The technique uses a pair of STEREO He II 304
Å images observed simultaneously. The STEREO-B image is geometrically
transformed to a STEREO-A view so that the background images appear
similar. Filaments, being elevated structures, i.e., not lying on the
same spherical surface as background features, do not appear similar
in the transformed view. Thus, subtracting the two images cancels
the background but leaves behind the filament structure. We apply this
technique to study the dynamics of the filament-eruption event of 22 May
2008, which was observed by STEREO and followed by several ground-based
observatories participating in the Joint Observing Programme (JOP 178).
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Title: A 3D view of eruptive filaments by STEREO
Authors: Gosain, Sanjay; Schmieder, Brigitte; Venkatakrishnan, P.;
Chandra, Ramesh; Artzner, Guy
2010cosp...38.2916G Altcode: 2010cosp.meet.2916G
STEREO/SECHI/EUVI A and B observe different views of the eruption of a
quiescent filament. We will concentrate on two events: (i) May 20 to 22,
2008 event (A and B separated by 52.4 degrees from each other), and (ii)
September 25 to 26, 2009 event (A and B more than 100 degrees from each
other. After using different techniques of reconstruction we obtained
a 3 dimensional view of untwisted flux ropes in He II 304 Angstrom,
with fine structures. The entire disappearance phase lasted more than
ten hours. The filament evolved very slowly ( 5 km/s) from a dense
structure with a thick spine into fine threads. Individual threads are
seen to be oscillating and rising to an altitude of about 150 Mm with
velocities of about 100 km/s. The plasma disappears by diffusion in
the corona. Weak CME events are recorded by LASCO at the beginning of
the disappearance. In this paper we shall present the dynamics of the
filament eruptions as viewed in 3D by STEREO using different methods. We
shall explore the causes and consequences of the filament disappearance.
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Title: 3D Evolution of a Filament Disappearance Event Observed
by STEREO
Authors: Gosain, S.; Schmieder, B.; Venkatakrishnan, P.; Chandra,
R.; Artzner, G.
2009SoPh..259...13G Altcode: 2009arXiv0910.0786G
A filament disappearance event was observed on 22 May 2008 during
our recent campaign JOP 178. The filament, situated in the Southern
Hemisphere, showed sinistral chirality consistent with the hemispheric
rule. The event was well observed by several observatories,
in particular by THEMIS. One day, before the disappearance, Hα
observations showed up- and down-flows in adjacent locations along the
filament, which suggest plasma motions along twisted flux rope. THEMIS
and GONG observations show shearing photospheric motions leading
to magnetic flux canceling around barbs. STEREO A, B spacecraft
with separation angle 52.4°, showed quite different views of this
untwisting flux rope in He II 304 Å images. Here, we reconstruct the
three-dimensional geometry of the filament during its eruption phase
using STEREO EUV He II 304 Å images and find that the filament was
highly inclined to the solar normal. The He II 304 Å movies show
individual threads, which oscillate and rise to an altitude of about
120 Mm with apparent velocities of about 100 km s<SUP>−1</SUP>
during the rapid evolution phase. Finally, as the flux rope expands
into the corona, the filament disappears by becoming optically thin to
undetectable levels. No CME was detected by STEREO, only a faint CME
was recorded by LASCO at the beginning of the disappearance phase at
02:00 UT, which could be due to partial filament eruption. Further,
STEREO Fe XII 195 Å images showed bright loops beneath the filament
prior to the disappearance phase, suggesting magnetic reconnection
below the flux rope.
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Title: Optique active et optique adaptative.
Authors: Artzner, G.
2006LAstr.120..349A Altcode:
No abstract at ADS
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Title: An atlas of solar events: 1996 2005
Authors: Artzner, G.; Auchère, F.; Delaboudinière, J. P.; Bougnet, M.
2006AdSpR..38..390A Altcode:
Coronal mass ejections (CMEs) are observed in the plane of the sky in
coronographic images. As the solar surface is masked by an occulting
disk it is not clear whether halo CMEs are directed towards or away
from the Earth. Observations of the solar corona on the solar disk
by the extreme ultraviolet imaging telescope (EIT) on board the Solar
Heliospheric Observatory SoHO can help to resolve this. Quasi-continuous
observations of the solar corona were obtained from April 1997 up to
the current date at a 12 min cadence in the coronal line of FeXII, as
part of a “CME watch program”. At a slower 6 h cadence an additional
synoptic program investigates the chromosphere and the corona at four
different wavelengths. Large coronal solar events appear when viewing
animations of the CME watch program. Fainter events do appear when
viewing running difference animations of the CME watch program. When
looking for additional spectral information from raw running differences
of the synoptic program it is difficult to disentangle intrinsic solar
events from the parasitic effect of the solar rotation. We constructed
at www.ias.u-psud.fr/medoc/EIT/movies/ an atlas of more than 40,000
difference images from the synoptic programme, corrected for an
average solar rotation, as well as more than 200,000 instantaneous and
difference images from the CME watch program. We present case studies
of specific events in order to investigate the source of darkenings or
dimmings in difference images, due to the removal of emitting material,
the presence of obscuring material or large changes in temperature. As
the beneficial effect of correcting for the solar rotation vanishes at
the solar limb, we do not investigate the case of prominence Doppler
dimming. As a by-product of the atlas of solar events we obtain a
number of quiet time sequences well suited to precisely measure the
differential solar rotation by the apparent displacement of tracers.
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Title: EIT Observations of the 15 November 1999 Mercury Transit
Authors: Auchère, F.; Artzner, G. E.
2004SoPh..219..217A Altcode:
The Mercury transit of 15 November 1999 has been observed from space
by the SOHO and TRACE spacecraft. We exploited the data recorded by
EIT/SOHO to determine the stray-light level and the plate-scale of
the instrument. The asymmetric distribution of stray light across the
images is confirmed, but the absolute amount was found to be higher
than previously estimated. The plate scale averaged over wavelengths
was found to be 2.627±0.001 arc sec pixel<SUP>−1</SUP>, in excellent
agreement with two previous and independent determinations.
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Title: EUVI: the STEREO-SECCHI extreme ultraviolet imager
Authors: Wuelser, Jean-Pierre; Lemen, James R.; Tarbell, Theodore
D.; Wolfson, C. J.; Cannon, Joseph C.; Carpenter, Brock A.; Duncan,
Dexter W.; Gradwohl, Glenn S.; Meyer, Syndie B.; Moore, Augustus S.;
Navarro, Rosemarie L.; Pearson, J. D.; Rossi, George R.; Springer,
Larry A.; Howard, Russell A.; Moses, John D.; Newmark, Jeffrey S.;
Delaboudiniere, Jean-Pierre; Artzner, Guy E.; Auchere, Frederic;
Bougnet, Marie; Bouyries, Philippe; Bridou, Francoise; Clotaire,
Jean-Yves; Colas, Gerard; Delmotte, Franck; Jerome, Arnaud; Lamare,
Michel; Mercier, Raymond; Mullot, Michel; Ravet, Marie-Francoise;
Song, Xueyan; Bothmer, Volker; Deutsch, Werner
2004SPIE.5171..111W Altcode:
The Extreme Ultraviolet Imager (EUVI) is part of the SECCHI instrument
suite currently being developed for the NASA STEREO mission. Identical
EUVI telescopes on the two STEREO spacecraft will study the structure
and evolution of the solar corona in three dimensions, and specifically
focus on the initiation and early evolution of coronal mass ejections
(CMEs). The EUVI telescope is being developed at the Lockheed Martin
Solar and Astrophysics Lab. The SECCHI investigation is led by the
Naval Research Lab. The EUVI"s 2048 x 2048 pixel detectors have a
field of view out to 1.7 solar radii, and observe in four spectral
channels that span the 0.1 to 20 MK temperature range. In addition to
its view from two vantage points, the EUVI will provide a substantial
improvement in image resolution and image cadence over its predecessor
SOHO-EIT, while complying with the more restricted mass, power, and
volume allocations on the STEREO mission.
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Title: An atlas of solar events: 1997-2004
Authors: Artzner, G.; Auchère, F.; Delaboudinière, J. P.; Bougnet, M.
2004cosp...35.2494A Altcode: 2004cosp.meet.2494A
Coronal mass ejections (CMEs) are observed in the plane of the sky
from coronographic images. As the solar surface is then masked by an
occulting disk, it is not clear wether halo CMEs are directed towards
the Earth or in the opposite direction. Observations of the solar corona
on the solar disk from the Extreme Ultraviolet Imaging Telescope EIT on
board the Solar Heliospheric Observatory SoHO do help in order to make
a choice. Quasi-continuous observations of the corona of the Sun have
been therefore obtained from april 1997 up to now at a twelve minute
cadence in the coronal line of FeXII, as a CME watch program. At a
slower six hours cadence an additional synoptic program investigates
the chromosphere and the corona at four different wavelengths. Large
coronal solar events appear when viewing animations of the CME watch
program. Fainter events do appear when viewing running difference
animations of the CME watch program. When looking for additional
spectral information from raw running differences of the synoptic
program it is difficult to disentangle intrinsic solar events from
the parasitic effect of the solar rotation. We constructed from the
synoptic program observations an atlas of more than 20 000 difference
images corrected for an average solar rotation. We present case studies
of specific events in order to investigate the source of darkenings in
difference images, either removal of emitting material, interposition
of obscuring material or large changes of temperature. Statistics
of brigtenings and darkenings along solar cycle 23 are presented. We
speculate about future observations from the STEREO mission in order
to obtain better diagnostics about darkenings. As a by product of the
atlas of solar events we obtain a number of quiet time sequences well
suited in order to precisely measure the differnetial solar rotation
by the apparent displacement of tracers.
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Title: Photon sieves as EUV telescopes for Solar Orbiter
Authors: Artzner, Guy E.; Delaboudiniere, Jean Pierre; Song, Xueyan
2003SPIE.4853..158A Altcode:
We elaborate about obtaining images of the solar disc and of the solar
corona at discrete wavelengths along the EUV emission solar spectrum
on board the Solar Orbiter spacecraft. Refractive optics cannot be
used. The thermal load is twenty five times higher than on a near Earth
orbit. As on one side the efficiency of a stenopeic device is too low,
and as on the other side mirrors exposed directly to the light and
to the particles emitted by the Sun may severely degrade during time,
we investigated using the EUV analog of a Fresnel lens, i.e. a photon
sieve. An opaque self supporting flat piece of heat resistant metal
let the solar light shine through a large numbers of a few thousand
holes properly designed in positions and diameters in order to obtain
constructive interferences at some focus. We report about practical
experiments in the visible.
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Title: MAGRITTE / SPECTRE : the Solar Atmospheric Imaging Assembly
(AIA) aboard the Solar Dynamics Observatory
Authors: Rochus, P.; Defise, J. M.; Halain, J. P.; Mazy, E.; Jamar, C.;
Clette, F.; Cugnon, P.; Berghmans, D.; Hochedez, J. F.; Delaboudiniere,
J. P.; Artzner, G.; Auchere, F.; Mercier, R.; Ravet, M. F.; Delmotte,
M.; Idir, M.; Fineschi, S.; Antonucci, E.; Harrison, R. A.; Howard,
R. A.; Moses, J. D.; Newmark, J. S.
2002AGUFMSH21C..05R Altcode:
The Solar Atmospheric Imaging Assembly (AIA) aboard the Solar
Dynamics Observatory will characterize the dynamical evolution of
the solar plasma from the chromosphere to the corona, and will follow
the connection of plasma dynamics with magnetic activity throughout
the solar atmosphere. The AIA consists of 7 high resolution imaging
telescopes in the following spectral bandpasses: 1215 \x8F Ly-a, 304
\x8F He II, 629 \x8F OV, 465 \x8F Ne VII, 195 \x8F Fe XII (includes Fe
XXIV), 284 \x8F Fe XV, and 335 \x8F Fe XVI. The telescopes are grouped
by instrumental approach: the Magritte Filtergraphs (R. Magritte,
famous 20th Century Belgian Surrealistic Artist), five multilayer EUV
channels with bandpasses ranging from 195 to 1216 \x8F, and the SPECTRE
Spectroheliograph with one soft-EUV channel at OV 629 \x8F. They will
be simultaneously operated with a 10-second imaging cadence. These two
instruments, the electronic boxes and two redundant Guide Telescopes
(GT) constitute the AIA suite. They will be mounted and coaligned on a
dedicated common optical bench. The GTs will provide pointing jitter
information to the whole SHARPP assembly. This poster presents the
selected technologies, the different challenges, the trade-offs to be
made in phase A, and the model philosophy. From a scientific viewpoint,
the unique combination high temporal and spatial resolutions with the
simultaneous multi-channel capability will allow Magritte/SPECTRE
to explore new domains in the dynamics of the solar atmosphere, in
particular the fast small-scale phenomena. We show how the spectral
channels of the different instruments were derived to fulfill the
AIA scientific objectives, and we outline how this imager array will
address key science issues, like the transition region and coronal waves
or flare precursors, in coordination with other SDO experiments. We
finally describe the real-time solar monitoring products that will be
made available for space-weather forecasting applications.
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Title: Transition region quiet sun velocity field evolution
Authors: Lemaire, P.; Artzner, G.; Vial, J. -C.; Curdt, W.; Schühle,
U.; Wilhelm, K.
2002AdSpR..30..487L Altcode:
The UV/EUV SUMER spectrometer aboard SOHO can record profiles of lines
emitted by elements at different stages of ionization corresponding
to several temperatures within the transition region temperature
range. During the solar cycle minimum in July 1996, we were able to
observe the quiet Sun during five consecutive days. From the line
positions we have determined the velocity fields and follow their time
variations at different temperatures in the transition region. The line
intensity maps are used to separate supergranular cells and network and
they allow to compare the behaviors of the velocity fields evolution in
the two structures. The results are critically analyzed and discussed.
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Title: Nulling interferometry for the DARWIN mission: experimental
demonstration of the concept in the thermal infrared with high levels
of rejection
Authors: Ollivier, Marc; Mariotti, Jean-Marie; Sekulic, Predrag;
Michel, Guy; Leger, Alain M.; Bouchareine, Patrick; Brunaud,
Jacqueline; Coudé du Foresto, Vincent; Mennesson, Bertrand P.; Borde,
Pascal J.; Amy-Klein, A.; Vanlerberghe, A.; Lagage, Pierre-Olivier;
Artzner, Guy E.; Malbet, Fabien
2000SPIE.4006..354O Altcode:
Present projects of space interferometers dedicated to the detection
and analysis of extrasolar planets (DARWIN in Europe, TPF in the United
States) are based on the nulling interferometry concept. This concept
has been proposed by Bracewell in 1978 but has never been demonstrated
with high values of rejection, in the thermal infrared range, where
the planet detection should be performed (6 - 18 micrometers ). We
have thus built a two-beam laboratory interferometer to validate this
concept in a monochromatic case (at 10 micrometers ). The keypoint
of our interferometer is the use of optical filtering by pinhole and
optical fibers to clean the interfering beams. We present in this
paper the principle of the experimental setup, its realization, and
the first measurements of rejection it allowed. We also present the
future developments of this interferometer.
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Title: In-Flight Determination of the Plate Scale of the
Extreme-Ultraviolet Imaging Telescope
Authors: Auchère, F.; DeForest, C. E.; Artzner, G.
2000ApJ...529L.115A Altcode:
Using simultaneous observations of the Michelson Doppler Imager
and Extreme-Ultraviolet Imaging Telescope (EIT) on board the Solar
and Heliospheric Observatory spacecraft, we determined in flight
the plate scale of the EIT. We found a value of 2.629"+/-0.001"
pixel<SUP>-1</SUP>, in fair agreement with the 2.627"+/-0.001"
pixel<SUP>-1</SUP> value deduced from recent laboratory measurements
of the focal length and much higher by 7 σ than the 2.622"
pixel<SUP>-1</SUP> value of the preflight calibrations. The plate
scale is found to be constant across the field of view, confirming
the negligible distortion level predicted by the theoretical models
of the EIT. Furthermore, the 2 σ difference between our results and
the latest laboratory measurements, although statistically small, may
confirm a recent work suggesting that the solar photospheric radius
may be 0.5 Mm lower than the classically adopted value of 695.99 Mm.
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Title: In Flight Determination of the Plate Scale of the EIT
Authors: Auchere, F.; DeForest, C. E.; Artzner, G.
1999astro.ph.12213A Altcode:
Using simultaneous observations of the MDI and EIT instruments on
board the SoHO spacecraft, we determined in flight the plate scale
of the EIT. We found a value of 2.629+-0.001 arc seconds per pixel,
in fair agreement with the 2.627+-0.001 arc seconds per pixel value
deduced from recent laboratory measurements of the focal length, and
much higher by 7 sigma than the 2.622 arc seconds per pixel value of
the pre-flight calibrations. The plate scale is found to be constant
across the field of view, confirming the negligible distortion level
predicted by the theoretical models of the EIT. Furthermore, the 2 sigma
difference between our results and the latest laboratory measurements,
although statistically small, may confirm a recent work suggesting that
the solar photospheric radius may be 0.5 Mm lower than the classically
adopted value of 695.99 Mm.
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Title: Spécial éclipse 11 aou^t 1999 - bilan.
Authors: Laurent, M.; Weulersse, P.; Delahaye, F.; Gredin, E.; Gredin,
P.; Roy, M.; Roy, H.; Arioli, H.; Boust, D.; Meeus, J.; Guillermier,
P.; Artzner, G.
1999LAstr.113..340L Altcode:
No abstract at ADS
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Title: An Eruptive Flare Observed by TRACE as a Test for the Magnetic
Authors: Aulaneir, G.; Deluca, E. E.; Golub, L.; Artzner, Guy; Sabine
Coquillart; Hochedez, Jean-Francois; Delaboudinier, Jean-Pierre
1999ESASP.446..131A Altcode: 1999soho....8..131A
No abstract at ADS
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Title: Equivalent focal length measurements
Authors: Artzner, Guy E.; Auchere, Frederic; Delaboudiniere,
Jean-Pierre; Hochedez, Jean-Francois E.
1999SPIE.3737...32A Altcode:
Converting linear coordinates in the plane of the detector of
an astronomical instrument to celestial coordinates involves in
principle the equivalent focal length of the instrument. However,
most methods in astrometry manage to reduce observations in a global
manner without actually measuring a focal length. We point out a case
for solar space observations where the long term stability of angular
distance measurements is better than the ground calibration of the
angular value of a pixel. We report and discuss this ground calibration.
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Title: Nulling Interferometry for the DARWIN Mission - Laboratory
Demonstration Experiment
Authors: Ollivier, M.; Léger, A.; Sekulic, C. Anceau. P.; Brunaud,
J.; Artzner, G.; Mariotti, J. -M.; Michel, G.; Coudé du Foresto,
V.; Mennesson, B.; Bouchareine, P.; Lépine, T.; Malbet, F.
1999ASPC..194..443O Altcode: 1999wfoi.conf..443O
The present projects of space interferometers dedicated to the detection
and analysis of extrasolar planets (DARWIN/IRSI in Europe, TPF in
the United States) are based on the nulling interferometry concept
(interferometrical coronography). This concept has been proposed by
Bracewell in 1979 but has never been demonstrated, with high values
of rejection, in the thermal infrared range where planet detection
should be performed (6-18 microns). We have thus built a two-beam
laboratory interferometer to validate this concept in a monochromatic
case (CO2 laser). We present the principle of the experimental setup,
its realisation, its sub-systems and their servo-control. We present
also the first results we got with this interferometer.
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Title: Observations of Coronal Structures Above an Active Region by
EIT and Implications for Coronal Energy Deposition
Authors: Neupert, W. M.; Newmark, J.; Delaboudinière, J. -P.;
Thompson, B. J.; Catura, R. C.; Moses, J. D.; Gurman, J. B.;
Portier-Fozzani, F.; Gabriel, A. H.; Artzner, G.; Clette, F.; Cugnon,
P.; Maucherat, A. J.; Defise, J. M.; Jamar, C.; Rochus, P.; Dere,
K. P.; Howard, R. A.; Michels, D. J.; Freeland, S.; Lemen, J. R.;
Stern, R. A.
1998SoPh..183..305N Altcode:
Solar EUV images recorded by the EUV Imaging Telescope (EIT) on SOHO
have been used to evaluate temperature and density as a function of
position in two largescale features in the corona observed in the
temperature range of 1.0-2.0 MK. Such observations permit estimates
of longitudinal temperature gradients (if present) in the corona and,
consequently, estimates of thermal conduction and radiative losses
as a function of position in the features. We examine two relatively
cool features as recorded in EIT's Fe ix/x (171 Å) and Fe xii (195 Å)
bands in a decaying active region. The first is a long-lived loop-like
feature with one leg, ending in the active region, much more prominent
than one or more distant footpoints assumed to be rooted in regions of
weakly enhanced field. The other is a near-radial feature, observed
at the West limb, which may be either the base of a very high loop
or the base of a helmet streamer. We evaluate energy requirements to
support a steady-state energy balance in these features and find in
both instances that downward thermal conductive losses (at heights
above the transition region) are inadequate to support local radiative
losses, which are the predominant loss mechanism. The requirement that a
coronal energy deposition rate proportional to the square of the ambient
electron density (or pressure) is present in these cool coronal features
provides an additional constraint on coronal heating mechanisms.
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Title: The prolate solar chromosphere
Authors: Auchere, F.; Boulade, S.; Koutchmy, S.; Smartt, R. N.;
Delaboudiniere, J. P.; Georgakilas, A.; Gurman, J. B.; Artzner, G. E.
1998A&A...336L..57A Altcode:
We present a comparative analysis of the chromospheric solar
limb prolateness, using strictly simultaneous H_alpha ground-based
observations and Heriptsize{II} space-based observations. The typical
prolateness is found to be Delta D/D=5.5*E(-3) in Heriptsize{II}
and 1.2*E(-3) in H_alpha . The first measurements in the 30.4 nm
Heriptsize{II} line over a period of two years, as well as coronal
data, are discussed to explore further the origin of the prolateness
and its possible consequences.
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Title: Aspherical wavefront measurements: Shack-Hartmann numerical
and practical experiments
Authors: Artzner, Guy
1998PApOp...7..435A Altcode:
No abstract at ADS
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Title: EIT Observations of the Extreme Ultraviolet Sun
Authors: Moses, D.; Clette, F.; Delaboudinière, J. -P.; Artzner,
G. E.; Bougnet, M.; Brunaud, J.; Carabetian, C.; Gabriel, A. H.;
Hochedez, J. F.; Millier, F.; Song, X. Y.; Au, B.; Dere, K. P.; Howard,
R. A.; Kreplin, R.; Michels, D. J.; Defise, J. M.; Jamar, C.; Rochus,
P.; Chauvineau, J. P.; Marioge, J. P.; Catura, R. C.; Lemen, J. R.;
Shing, L.; Stern, R. A.; Gurman, J. B.; Neupert, W. M.; Newmark,
J.; Thompson, B.; Maucherat, A.; Portier-Fozzani, F.; Berghmans, D.;
Cugnon, P.; Van Dessel, E. L.; Gabryl, J. R.
1997SoPh..175..571M Altcode:
The Extreme Ultraviolet Imaging Telescope (EIT) on board the SOHO
spacecraft has been operational since 2 January 1996. EIT observes
the Sun over a 45 x 45 arc min field of view in four emission line
groups: Feix, x, Fexii, Fexv, and Heii. A post-launch determination
of the instrument flatfield, the instrument scattering function, and
the instrument aging were necessary for the reduction and analysis
of the data. The observed structures and their evolution in each
of the four EUV bandpasses are characteristic of the peak emission
temperature of the line(s) chosen for that bandpass. Reports on the
initial results of a variety of analysis projects demonstrate the range
of investigations now underway: EIT provides new observations of the
corona in the temperature range of 1 to 2 MK. Temperature studies of
the large-scale coronal features extend previous coronagraph work
with low-noise temperature maps. Temperatures of radial, extended,
plume-like structures in both the polar coronal hole and in a low
latitude decaying active region were found to be cooler than the
surrounding material. Active region loops were investigated in detail
and found to be isothermal for the low loops but hottest at the loop
tops for the large loops.
---------------------------------------------------------
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: Association of Extreme-Ultraviolet Imaging Telescope (EIT)
Polar Plumes with Mixed-Polarity Magnetic Network
Authors: Wang, Y. -M.; Sheeley, N. R.; Dere, K. P.; Duffin, R. T.;
Howard, R. A.; Michels, D. J.; Moses, J. D.; Harvey, J. W.; Branston,
D. D.; Delaboudinière, J. -P.; Artzner, G. E.; Hochedez, J. F.;
Defise, J. M.; Catura, R. C.; Lemen, J. R.; Gurman, J. B.; Neupert,
W. M.; Newmark, J.; Thompson, B.; Maucherat, A.; Clette, F.
1997ApJ...484L..75W Altcode:
SOHO EIT spectroheliograms showing the polar coronal holes during the
present sunspot minimum are compared with National Solar Observatory
(Kitt Peak) magnetograms taken in Fe I λ8688 and Ca II λ8542. The
chromospheric λ8542 magnetograms, obtained on a routine, near-daily
basis since 1996 June, reveal the Sun's strong polar fields with
remarkable clarity. We find that the Fe IX λ171 polar plumes occur
where minority-polarity flux is in contact with flux of the dominant
polarity inside each polar hole. Moreover, the locations of “plume
haze” coincide approximately with the patterns of brightened He
II λ304 network within the coronal hole. The observations appear
to be consistent with mechanisms of plume formation involving
magnetic reconnection between unipolar flux concentrations and nearby
bipoles. The fact that minority-polarity fields constitute only a small
fraction of the total magnetic flux within the polar holes suggests
that plumes are not the main source of the high-speed polar wind.
---------------------------------------------------------
Title: Observations of Coronal Features by EIT above an Active Region
by EIT and Implications for Coronal Heating
Authors: Neupert, W. M.; Newmark, J.; Thompson, B. J.; Catura, R.;
Moses, J. D.; Portier-Fozzani, F.; Delaboudiniere, J. P.; Gabriel, A.;
Artzner, G.; Clette, F.; Cugnon, P.; Maucherat, A.; Defise, J. M.;
Jamar, C.; Rochus, P.; Howard, R.; Michels, D.; Dere, K.; Freeland,
S.; Lemen, J.; Stern, R.; Gurman, J.
1997SPD....28.0115N Altcode: 1997BAAS...29..881N
The EUV Imaging Telescope (EIT) on the SOHO provides the capability
for multi-wavelength imaging of the corona in four spectral bands,
centered at 171, 195, 284, and 304 Angstroms, using multilayer telescope
technology. These bands encompass coronal temperatures from 1 MK
to 2.5 MK as well as the upper chromosphere, at about 60,000 K. In
particular, nearly simultaneous imaging in the 171 and 195 Angstrom
bands, the former including major Fe IX and Fe X emission lines, the
latter including a strong Fe XII line, provides a capability to infer
the morphology and characteristics of the corona at temperatures of
1.0 - 1.7 MK. We have examined the corona in this temperature range
over an active region observed from SOHO from May - September, 1996 and
find that low-lying loops (below a density scale height of 75,000 km,
characteristic of Fe X) vary little in brightness and temperature along
their length. For features extending to greater heights, however, both
brightness gradients and temperature gradients are observed. Preliminary
analysis of the observations when the region was on the West limb
on September 30 indicates a small positive temperature gradient of
approximately 0.5 K/km in one loop system that extended above 100,000
km. On the other hand, a nearly radial feature extending to the edge of
the EIT FOV was isothermal or had at most a slight negative temperature
gradient. Such measurements may have application to the modeling of
coronal loops and streamers and the processes of coronal heating and
solar wind acceleration.
---------------------------------------------------------
Title: Imaging the solar corona in the EUV
Authors: Delaboudiniere, J. -P.; Stern, R. A.; Maucherat, A.;
Portier-Fozzani, F.; Neupert, W. M.; Gurman, J. B.; Catura, R. C.;
Lemen, J. R.; Shing, L.; Artzner, G. E.; Brunaud, J.; Gabriel, A. H.;
Michels, D. J.; Moses, J. D.; Au, B.; Dere, K. P.; Howard, R. A.;
Kreplin, R.; Defise, J. M.; Jamar, C.; Rochus, P.; Chauvineau, J. P.;
Marioge, J. P.; Clette, F.; Cugnon, P.; van Dessel, E. L.
1997AdSpR..20.2231D Altcode:
The SOHO (SOlar and Heliospheric Observatory) satellite was launched on
December 2nd 1995. After arriving at the Earth-Sun (L1) Lagrangian point
on February 14th 1996, it began to continuously observe the Sun. As
one of the instruments onboard SOHO, the EIT (Extreme ultraviolet
Imaging Telescope) images the Sun's corona in 4 EUV wavelengths. The
He II filter at 304 A˚ images the chromosphere and the base of the
transition region at a temperature of 5 - 8 x 10^4 K; the Fe IX-X
filter at 171 A˚ images the corona at a temperature of ~ 1.3 x 10^6 K;
the Fe XII filter at 195 A˚ images the quiet corona outside coronal
holes at a temperature of ~ 1.6 x 10^6 K; and the Fe XV filter at 284
A˚ images active regions with a temperature of ~ 2.0 x 10^6 K. About
5000 images have been obtained up to the present. In this paper,
we describe also some aspects of the telescope and the detector
performance for application in the observations. Images and movies
of all the wavelengths allow a look at different phenomena present in
the Sun's corona, and in particular, magnetic field reconnection.
---------------------------------------------------------
Title: First Results from EIT
Authors: Clette, F.; Delaboudiniere, J. -P.; Artzner, G. E.; Brunaud,
J.; Gabriel, A. H.; Hochedez, J. -F.; Millier, F.; Song, X. Y.; Au, B.;
Dere, K. P.; Howard, R. A.; Kreplin, R.; Michels, D. J.; Moses, J. D.;
Defise, J. -M.; Jamar, C.; Rochus, P.; Chauvineau, J. -P.; Marioge,
J. -P.; Catura, R. C.; Lemen, J. R.; Shing, L.; Stern, R. A.; Gurman,
J. B.; Neupert, W. M.; Maucherat, A.; Cugnon, P.; van Dessel, E. L.
1997ASPC..118..268C Altcode: 1997fasp.conf..268C
The Extreme-UV Imaging telescope has already produced more than 15000
wide-field images of the corona and transition region, on the disk
and up to 1.5R_⊙ above the limb, with a pixel size of 2.6\arcsec. By
using four different emission lines, it provides the global temperature
distribution in the quiet corona, in the range 0.5 to 3*E(6) K. Its
excellent sensitivity and wide dynamic range allow unprecedented views
of low emission features, even inside coronal holes. Those so-called
“quiet” regions actually display a wide range of dynamical phenomena,
in particular at small spatial scales and at time scales going down
to only a few seconds, as revealed by all EIT time sequences of
full- or partial-field images. The initial results presented here
demonstrate the importance of this wide-field imaging experiment for
a good coordination between SOHO and ground-based solar telescopes,
as well as for science planning.
---------------------------------------------------------
Title: Observations of the South coronal hole from EIT and YOHKOH
Authors: Handy, B. N.; Catura, R.; Freeland, S.; Lemen, J.; Stern,
R.; Gurman, J. B.; Delaboudiniere, J. P.; Artzner, G.; Gabriel, A.;
Maucherat, A.; Defise, J. M.; Jamar, C.; Rochus, P.; Clette, F.;
Cugnon, P.; Howard, R.; Michels, D.; Moses, J. D.; Dere, K.; Cyr,
O. C. St.; Catura, R.; Freeland, S.; Lemen, J.; Stern, R.; Neupert,
W.; Einfalt, E.; Newmark, J.
1996AAS...188.0206H Altcode: 1996BAAS...28..821H
The Extreme ultraviolet Imaging Telescope (EIT) on board the
SOHO spacecraft is capable of studying solar transition region,
chomospheric and coronal plasmas over bandpasses optimized for He II
304 Angstroms (0.08 MK), Fe IX/X 171, 173 Angstroms (0.8 - 1.0 MK),
Fe XII 195 Angstroms (1.5 MK), and Fe XV 284 Angstroms (2.0 - 2.5
MK) with 2.5 arcsecond spatial resolution. This telescope in concert
with the Yohkoh/SXT instrument allows us to simultaneously observe
solar structures at temperatures ranging from less than 0.1MK in the
transition region to over 3MK in the solar corona. EIT has had several
opportunities to observe the South coronal hole with high spatial and
temporal resolution. We compare observations from EIT and SXT with
an eye towards correlating temporal variations over the range of
wavelengths, activity of polar crown filament systems and relating
large-scale morphology of the X-ray corona to the transition region
in He II.
---------------------------------------------------------
Title: There's No Such Thing as the Quiet Sun: EUV Movies from SOHO
Authors: Gurman, J. B.; Delaboudiniere, J. P.; Artzner, G.; Gabriel,
A.; Maucherat, A.; Defise, J. M.; Jamar, C.; Rochus, P.; Clette, F.;
Cugnon, P.; Howard, R.; Michels, D.; Moses, J. D.; Dere, K.; Cyr,
O. C. St.; Catura, R.; Freeland, S.; Lemen, J.; Stern, R.; Neupert,
W.; Einfalt, E.; Newmark, J.
1996AAS...188.3718G Altcode: 1996BAAS...28..880G
We present unique time series of high-resolution solar images from the
normal-incidence Extreme ultraviolet Imaging Telescope (EIT) on board
the SOHO spacecraft. With a pixel scale of 2.6 arc sec and a detector
dynamic range of > 10(4) , the EIT can be used to study the dynamics
of chromospheric and coronal features in multilayer bandpasses optimized
for He II 304 Angstroms (0.08 MK), Fe IX/X 171, 173 Angstroms (0.8 -
1.0 MK), Fe XII 195 Angstroms (1.5 MK), and Fe XV 284 Angstroms (2.0 -
2.5 MK). Among the most striking features of the digital movies we will
display are: the dynamic nature of small-scale loop features in the
polar coronal holes, the constant activity of the polar crown filament
systems, the locations of the bases of polar plumes, the presence
of dark (scattering) filament material in the coronal emission line
images, and the evolution of a unique, linear, dark feature in a young
active region. The latter feature is suggestive of the “coronal void”
observed in the electron scattering corona by Macqueen et al./ (1983).
---------------------------------------------------------
Title: Observations of the south coronal hole from EIT and Yohkoh.
Authors: Handy, B. N.; Catura, R.; Freeland, S.; Lemen, J.; Stern,
R.; Gurman, J. B.; Delaboudinière, J. P.; Artzner, G.; Gabriel,
A.; Maucherat, A.; Defise, J. M.; Jamar, C.; Rochus, P.; Clette, F.;
Cugnon, P.; Howard, R.; Michels, D.; Moses, J. D.; Dere, K.; St. Cyr,
O. C.; Neupert, W.; Einfalt, E.; Newmark, J.
1996BAAS...28Q.821H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: EIT: Extreme-Ultraviolet Imaging Telescope for the SOHO Mission
Authors: Delaboudinière, J. -P.; Artzner, G. E.; Brunaud, J.; Gabriel,
A. H.; Hochedez, J. F.; Millier, F.; Song, X. Y.; Au, B.; Dere, K. P.;
Howard, R. A.; Kreplin, R.; Michels, D. J.; Moses, J. D.; Defise,
J. M.; Jamar, C.; Rochus, P.; Chauvineau, J. P.; Marioge, J. P.;
Catura, R. C.; Lemen, J. R.; Shing, L.; Stern, R. A.; Gurman, J. B.;
Neupert, W. M.; Maucherat, A.; Clette, F.; Cugnon, P.; Van Dessel,
E. L.
1995SoPh..162..291D Altcode:
The Extreme-ultraviolet Imaging Telescope (EIT) will provide wide-field
images of the corona and transition region on the solar disc and up to
1.5 R⊙ above the solar limb. Its normal incidence multilayer-coated
optics will select spectral emission lines from Fe IX (171 å), Fe
XII (195 å), Fe XV (284 å), and He II (304 å) to provide sensitive
temperature diagnostics in the range from 6 × 10<SUP>4</SUP> K to 3
× 10<SUP>6</SUP> K. The telescope has a 45 x 45 arcmin field of view
and 2.6 arcsec pixels which will provide approximately 5-arcsec spatial
resolution. The EIT will probe the coronal plasma on a global scale,
as well as the underlying cooler and turbulent atmosphere, providing
the basis for comparative analyses with observations from both the
ground and other SOHO instruments. This paper presents details of the
EIT instrumentation, its performance and operating modes.
---------------------------------------------------------
Title: Calibration of the EIT instrument for the SOHO mission
Authors: Defise, Jean-Marc; Song, Xueyan Y.; Delaboudiniere,
Jean-Pierre; Artzner, Guy E.; Carabetian, Charles; Hochedez,
Jean-Francois E.; Brunaud, Jacqueline; Moses, John D.; Catura,
Richard C.; Clette, Frederic; Maucherat, Andre J.
1995SPIE.2517...29D Altcode:
Optical characteristics in the wavelength range 15 - 75 nm of the
EUV imaging telescope to be launched soon on the SOHO mission are
discussed. Bandpasses and photometric sensitivity of the multilayered
optics telescope have been measured by a dedicated synchrotron light
source at Orsay, France.
---------------------------------------------------------
Title: Fabrication and optical characteristics of microlens arrays
engraved in photoresist coatings
Authors: Gex, Francoise; Roblin, Gerard; Artzner, Guy E.; Bernstein,
L.; Horville, David; Serpette, V.
1993SPIE.1781..287G Altcode:
We have developed a technique for fabricating microlens arrays by
engraving photoresist coatings. These microlens arrays are designed for
astronomical applications for atmospheric wavefront sensors. First,
we describe the apparatus and the manufacturing process. Second, we
review the characteristics of the different photoresist types used
in this process. Third, we report on the different optical testing
methods to measure the microlens' performances. Then we deduce the
several inherent advantages and limitations of this method. Fourth,
we show how to produce monolithic arrays using ion beam milling with
photoresist microlens arrays as a pattern and we demonstrate how these
arrays can improve upon the performances of photoresist arrays.
---------------------------------------------------------
Title: Towards a dark matter experiment: performance of a 24g
sapphire bolometer
Authors: de Marcillac, P.; Coron, N.; Artzner, G.; Leblanc, J.; Torre,
J. P.; Goldbach, C.; Nollez, G.; Vidal-Madjar, A.; Mangin, J.
1992daec.conf..403D Altcode: 1992daec.conf..403M
I review here the debate on the nature of compact groups of galaxies:
are the compact groups catalogued by Hickson physically dense systems
or are they caused by chance alignments within larger systems? Results
of recent N-body simulations of loose groups are analyzed, showing
that only 10% of compact configurations seen in projection are three
dimensional dense systems (of which roughly half are bound), whereas
the remaining 90% are one dimensional chance alignments. Moreover,
these chance alignments turn out to be binary-rich (with a small
fraction of triplets too). The arguments reviewed here and these last
two results suggest that rather than being dense quartets and quintets,
most compact groups are binary-rich chance alignments within larger
systems, thus providing a natural explanation to the high level of
physical interactions seen in compact groups. Moreover, it is suggested
that the most distant compact groups may represent the bright-ends of
rich evolved clusters.
---------------------------------------------------------
Title: Solar corona synoptic observations from SOHO with an Extreme
Ultraviolet Imaging Telescope.
Authors: Delaboudinière, J. P.; Gabriel, A. H.; Artzner, G. E.;
Dere, K.; Howard, R.; Michels, D.; Catura, R.; Lemen, J.; Stern, R.;
Gurman, J.; Neupert, W.; Cugnon, P.; Koeckelenbergh, A.; van Dessel,
E. L.; Jamar, C.; Maucherat, A.
1992ESASP.348...21D Altcode: 1992cscl.work...21D
The major scientific objective of the EUV Imaging Telescope (EIT)
is to study the evolution of coronal structure over a wide range
of spatial and temporal scales and temperatures. A second strategic
objective is to provide full disk synoptic maps of the global corona
to aid in unifying SOHO (Solar and Heliospheric Observatory)/Cluster
investigations. EIT will also provide images to support the planning
of detailed spectroscopic investigations by the CDS (Coronal Diagnostic
Spectrometer) and SUMER spectrometers in SOHO. EIT observations will be
made in four narrow spectral bands, centered at 171 A (Fe 9), 195 A(Fe
12), 284 A (Fe 15), and 304 A (He 2) representing restricted temperature
domains within a wide temperature range from 40,000 to 3,000,000
K. The results will be images of the solar atmosphere from the upper
chromosphere and transition region to the active region corona. These
maps, made at appropriate time intervals, will be used to study the fine
structures in the solar corona and to relate their dynamic properties
to the underlying chromosphere and photosphere. Dynamic events in the
inner corona will be related to white light transients in the outer
corona, and observations of the internal structure of coronal holes
will be used to investigate origins of the solar wind.
---------------------------------------------------------
Title: Microlens arrays for Shack-Hartmann wavefront sensors
Authors: Artzner, Guy
1992OptEn..31.1311A Altcode:
Microlens arrays are a component of atmospheric wavefront sensors
used recently with success by ground-based astronomers to obtain
diffraction-limited images of stars in spite of wavefront disturbances
introduced by the earth's atmosphere. Typical requirements for
individual lenses are a size measured in tenths of millimeters, a sag
measured in micrometers, and no room left between lenses, i.e., square
or hexagonal lenses rather than circular lenses. Actual monolithic
square microlens arrays up to 20 x 20 mm in size for 0.18- to 1.5-mm
individual contiguous lenses of 0.0035-mm maximum sag are engraved in
photoresist coatings by a two-axes rastering process. These arrays have
been used for diurnal and nocturnal atmospheric wavefront measurements.
---------------------------------------------------------
Title: Rotational aperture synthesis: a proposal for ground-based
observations.
Authors: Artzner, Guy
1992ESASP.344..273A Altcode: 1992spai.rept..273A
Attention is drawn to the existence of three-axes equatorial mounts
for ground-based observing. The additional third axis with respect
to a conventional two axes equatorial or alt-az mount allows to set
the position angle at almost any predetermined value when observing
close to the zenith. In addition to that the quasi-total absence of
cantilever parts is an asset for interferometric stability. If the
SIMURIS strategy uses some breadboard for fine structure imaging
on the ground in the visible domain as an intermediate step between
laboratory developments and flight operations the author investigates
tactics for solar or stellar interferometric observations.
---------------------------------------------------------
Title: Solar Astrometry by Photolithography
Authors: Artzner, G.
1990SoPh..128..281A Altcode: 1990IAUCo.121P.281A
Observed temporal variations of shape and size of the solar disk as
viewed from Earth may act as constraints for theories of the interior of
the Sun. In addition to existing programs of solar diameter measurements
we investigate a ground-based photographic method.
---------------------------------------------------------
Title: Massive composite bolometers for dark matter detection.
Authors: Coron, N.; de Marcillac, P.; Artzner, G.; Leblanc, J.;
Jegoudez, G.; Dambier, G.; Lepeltier, J. P.; Barthelemy, M.;
Rothenflug, R.; Pari, P.; Tarrius, A.; Amoudry, F.; Stroke, H.;
Testard, O.
1990qfcc.proc..275C Altcode:
Massive composite bolometers cooled below 0.1K can detect recoil
energy of particles with a very high efficiency. By using different
absorber materials (Al<SUB>2</SUB>O<SUB>3</SUB>, Ge, Si, LiF,
Cr<SUB>2</SUB>O<SUB>3</SUB>, TiO<SUB>2</SUB>...) some identification
of dark matter particles will be possible. Resolutions in the 10 eV
range for 1 kg of absorber material are theoretically possible at 0.01K
if the thermistor is well matched to the substrate. The authors have
successfully developed and tested a 25 g sapphire bolometer at 0.1K
and have obtained for a 60 keV gamm-line a resolution of 16 keV FWHM,
limited by extraneous noise. First bolometric spectra of radioactivity
and cosmic ray backgrounds obtained at sea level are presented.
---------------------------------------------------------
Title: Extreme ultraviolet imaging telescope on board the Solar
Heliospheric Observatory
Authors: Delaboudiniere, Jean-Pierre; Gabriel, Alan H.; Artzner,
Guy E.; Millier, F.; Michels, Donald J.; Dere, Kenneth P.; Howard,
Russell A.; Kreplin, Robert W.; Catura, Richard C.; Stern, Robert A.;
Lemen, James R.; Neupert, Werner M.; Gurman, Joseph B.; Cugnon, P.;
Koeckelenbergh, A.; van Dessel, E. L.; Jamar, Claude A.; Maucherat,
Andre J.; Chauvineau, Jean-Pierre; Marioge, Jean-Paul
1989SPIE.1160..518D Altcode: 1989xeoa.conf..518D
The design of the multibandpass Extreme-Ultraviolet Imaging Telescope
designed for 1996 launch on board the Solar Heliospheric Observatory
is described. The telescope will observe simultaneously distinct
temperature ranges in the solar corona, defined by well chosen emission
lines. Images in four narrow bandpasses at wavelengths ranging from 17
to 31 nm will be obtained using normal-incidence multilayered optics
deposited on quadrants of a Ritchey-Chretien telescope. Results are
presented on the performances measured on a 2/3 scale mock-up. The
bandpasses could be adjusted to better than 1 percent in wavelength.
---------------------------------------------------------
Title: Static wavefront correction by Linnik interferometry.
Authors: Artzner, G.
1989SPIE.1013..233A Altcode:
The author considers optical systems with residual peak to valley
wavefront errors below 150 nm. The interference figure for λ =
633 nm may then be adjusted and photographed as to hold out at every
point of the image of the pupil a one to one relationship between the
optical density of the interferogram and the magnitude of the wavefront
error. An enduring interference figure is secured by means of a tiny
reflecting aluminized spot on a bare substrate located on the image
of a distant point source. The author investigates how subsequent
photoreproduction of an interferogram upon a photoresist coating may
act as a transmitting or reflecting wavefront corrector.
---------------------------------------------------------
Title: EIT: Solar corona synoptic observations from SOHO with an
Extreme-ultraviolet Imaging Telescope
Authors: Delaboudiniere, J. P.; Gabriel, A. H.; Artzner, G. E.;
Michels, D. J.; Dere, K. P.; Howard, R. A.; Catura, R.; Stern, R.;
Lemen, J.; Neupert, W.
1988sohi.rept...43D Altcode:
The Extreme-ultraviolet Imaging Telescope (EIT) of SOHO (solar and
heliospheric observatory) will provide full disk images in emission
lines formed at temperatures that map solar structures ranging from
the chromospheric network to the hot magnetically confined plasma in
the corona. Images in four narrow bandpasses will be obtained using
normal incidence multilayered optics deposited on quadrants of a
Ritchey-Chretien telescope. The EIT is capable of providing a uniform
one arc second resolution over its entire 50 by 50 arc min field of
view. Data from the EIT will be extremely valuable for identifying
and interpreting the spatial and temperature fine structures of the
solar atmosphere. Temporal analysis will provide information on the
stability of these structures and identify dynamical processes. EIT
images, issued daily, will provide the global corona context for aid
in unifying the investigations and in forming the observing plans for
SOHO coronal instruments.
---------------------------------------------------------
Title: Astronomical optics: Zonal aberration correction - Laboratory
experiments and extrapolations to space- and ground-based observations
Authors: Artzner, G.
1987A&A...175..345A Altcode:
The author describes the results of a laboratory experiment with a
143 mm diameter Cassegrainian telescope plagued by static irregular
zonal aberrations with rotational symmetry and 620 nm peak to valley
amplitude wavefront error. An adapted 16 mm useful diameter intrafocal
corrector plate has been surfaced using a 2 μ-thickness photoresist
coating on an optical substrate, ad-hoc non-uniform exposure via a
two-axis computercontrolled scanning device and subsequent development
and baking. The effect of losses by diffusion and absorption due to the
corrector plate is small with respect to the increase of contrast due
to the wavefront correction. Three extrapolations of this experiment
are discussed: (1) How to use correctors in the UV range where the size
of the Airy disk becomes smaller for a given aperture. (2) Correction
of aberrations with no rotational symmetry. (3) Feasible correctors
and relay optics adapted to large (4-8 m diameter) instruments have
a 50 mm corrected field, well matched to modern image detectors.
---------------------------------------------------------
Title: Aspherical surfaces engraved on photoresist coatings:
manufacture of a zonal corrector plate for an aberrating Cassegrainian
telescope.
Authors: Artzner, G.
1987SPIE..805..162A Altcode:
We investigate how aspherical optical surfaces engraved in photoresist
coatings avail against static wavefront aberrations up to 3 μ. The
spherical aberration of a singlet lens is corrected for. The image
given by a cassegrainian telescope of 143 mm diameter with a peak to
valley 0,62 µ wavefront error and 7" slopes is improved by a 16 mm
diameter intrafocal phase equalizer corrector plate. We then discuss
extrapolations of our laboratory experiments.
---------------------------------------------------------
Title: Bolometers as particle spectrometers
Authors: Stroke, H. H.; Artzner, G.; Coron, N.; Dambier, G.; Hansen,
P. G.
1986ITNS...33..759S Altcode:
A spectrometer based on low-temperature calorimetry has been under
development since 1983. The present detector, capable of recording
individual alpha and beta particles and X-ray photons, is based
on a composite diamond-germanium bolometer. The advantage of a
composite bolometer is that it separates the absorption and detection
functions. Diamond, as an absorber, is of particular advantage
because of its low heat capacity and high thermal diffusivity. The
goal is a theoretical energy resolution of a few eV at 0.1 K. Initial
experiments at 1.3 K and 0.9 K, which give resolutions in the keV range,
are still noise-limited. High-resolution applications, such as in X-ray
astronomy and nuclear physics (in particular, neutron mass measurements)
are foreseen.
---------------------------------------------------------
Title: Composite bolometers as spectrometers for X-ray astronomy
Authors: Coron, N.; Artzner, G.; Dambier, G.; Jegoudez, G.; Leblanc, J.
1986SPIE..597..389C Altcode:
The detection of single events like the absorption of gamma or X-rays
and alpha or beta particles with cooled thermal detectors is now
well established and first resolutions obtained are promising. The
paper investigates the possibilities of the composite bolometer which
offers the advantage of separating the absorption, thermal diffusion
and thermometric functions. An optimal configuration is the diamond
composite bolometer with a monolithic thermistor. Experimental results
are presented on the simultaneous detection of different kinds of events
at 1 K temperature. These results confirm the high linearity of this
detector and its ability to accept rather high counting rates. As a
conclusion, an example of application to X-ray astronomy is presented
and some problems or developments to be studied for a space mission
are underlined.
---------------------------------------------------------
Title: Bolometers as spectrometers for X-ray astronomy.
Authors: Coron, N.; Artzner, G.; Dambier, G.; Jegoudez, G.; Leblanc,
J.; Deschamps, J. Y.; Rocchia, R.; Tarrius, A.; Testard, O.; Ravn,
H. R.; Stroke, H. H.; Jonson, B.
1985ESASP.239..229C Altcode: 1985cxrs.work..229C
The authors have investigated the possibility to use composite
diamond-germanium bolometers, originally developed for I.R. astronomy,
for the individual detection of X-ray photons.
---------------------------------------------------------
Title: On the possible use of deep U.V. photoresists correctors to
obtain the ultimate U.V. resolution of space borne telescopes.
Authors: Dame, L.; Bonnet, R. M.; Artzner, G. E.
1984SPIE..445..318D Altcode:
Large space-borne telescopes are limited in their ultraviolet resolution
by their large and medium scale (20 - 30 cm) surface irregularities
(ripples). The authors present the principle, instrumentation and
first results of a new interferometric method using a Michelson-Twyman
configuration (diverging light beams) that allows to engrave on
deep U.V. photoresists a phase compensating plate which permit to
revocer, partly or entirely, the diffraction limited resolution of the
telescope. The corrector that they obtain is a phase compensating plate
in reflection with highs and lows on its surface perfectly conjugated
in negative, with the primary mirror surface irregularities.
---------------------------------------------------------
Title: Solar H-Lyman-α Flux and Profile Relative Measurements from
OSO-8: January 1976 to March 1978
Authors: Artzner, G.
1983wcrs.proc...87A Altcode:
More than 1,900 monochromatic full solar disk raster images of the H
Lyman-alpha 121.6-nm line have been calibrated by reference to nearly
simultaneous profiles of the Lyman-alpha line emitted by small, quiet
areas of the solar disk. The observations and the calibration procedures
are described. Values of the full line flux vary in a relative range
1 to 1.5 between January 1976 and March 1978. A hypothetical 35 to
60 percent variation of the solar flux between July 1976 and October
1977, as published with Atmosphere Explorer E results, is likely to
be closer to 30 to 35 percent. Any variation of the shape of the full
disk Lyman-alpha line profile is undetectable between December 9,
1976 and May 10, 1978.
---------------------------------------------------------
Title: Structure and Physics of Solar Faculae - Part Two - the
Non-Thermal Velocity Field above Faculae
Authors: Mouradian, Z.; Dumont, S.; Pecker, J. -C.; Chipman, E.;
Artzner, G. E.; Vial, J. C.
1982SoPh...78...83M Altcode:
The OSO-8 satellite enabled us to study various characteristics of
the profiles of Si II, Si IV, C IV, and O VI lines above active areas
of the Sun, as well as above quiet areas, and to derive some physical
properties of the transition region between chromosphere and corona
(CCT): (i) The study of the lines shows a general tendency for the
microvelocity fields on the average to be nearly constant for the
heights corresponding to T > 10<SUP>5</SUP> K; however they seem
to slightly increase with height in quiet areas, and decrease in
active areas. (ii) A multicomponent model of the CCT is however quite
necessary, and its geometry is far from being a set of plane-parallel
columns. It is similar to an association of moving knots within the
non-moving principal component of the matter. (iii) The proportion
of mass, in the knots relative to that in the non-moving component,
is several times larger in active regions than in quiet regions. (iv)
In the knots, the non-thermal microvelocity fields are smaller in active
regions and seem to decrease for T increasing above 10<SUP>5</SUP> K,
contrary to what happens in the steady principal component. Of course,
we consider that microturbulence and Doppler shift are two aspects of
the same distribution of velocity.
---------------------------------------------------------
Title: Physical properties of the solar chromosphere deduced from
optically thick lines. I - Observations, data reduction, and modelling
of an average plage
Authors: Lemaire, P.; Gouttebroze, P.; Vial, J. C.; Artzner, G. E.
1981A&A...103..160L Altcode:
Simultaneous Ca II H and K, Mg II h and k, and H I Lyman-alpha and
Lyman-beta profiles have been recorded by the OSO-8/LPSP spectrometer on
a quiet sun area and a part of plage, McMath 13738. After data reduction
and filtering, a full set of calibrated profiles is obtained. Using
a code developed at LPSP (Gouttebroze et al., 1978), profiles
computed from VAL III model C (Vernazza et al., 1981) are compared
to observations. A specific plage model has been computed to fit the
observed profiles. This model reproduces successfully Ca II H and K,
and H I Lyman-alpha and Lyman-beta, but partly fails with Mg II h and
k. Atmospheric inhomogeneities and dynamical effects may contribute to
this discrepancy, and it is proposed that the level number entering
in the Mg II computation be increased to take account of a likely
fluorescence induced by the H I Lyman-beta radiation field.
---------------------------------------------------------
Title: Absorption feature observed on the H Lyman-alpha solar line -
an interpretation
Authors: Artzner, G.; Cazes, S.; Emerich, C.; Vial, J. C.; Lemaire, P.
1981A&A...100..205A Altcode:
A narrow absorption feature on the red part of the solar H Lyman-alpha
profile has been observed by two instruments in 1975 and attributed
to atomic hydrogen of the nearby interplanetary gas. This hypothesis
implies that the absorption feature shifts with the position of the
earth on its orbit. New measurements above active regions at other
seasons rule out this hypothesis. On the other hand, appropriate
laboratory calibrations indicate that the absorption feature is likely
due to a ghost image of the geocoronal absorption.
---------------------------------------------------------
Title: OSO-8 Observations of CAII H and K MGII H and K Lyman-Alpha
and Lyman-Beta above a Sunspot
Authors: Kneer, F.; Scharmer, G.; Mattig, W.; Wyller, A.; Artzner,
G.; Lemaire, P.; Vial, J. C.
1981SoPh...69..289K Altcode:
Observations with the French (L.P.S.P.) experiment on board OSO-8 of
a sunspot and nearby plage region are described. The behaviour of the
emission cores of the Ca II H and K and Mg II h and k resonance lines is
very similar and the correspondence in intensity between the four lines
persists in all observed features. In contrast, the Lyman lines show
little correlation with the other lines. Their emission regions appear
broader in the spectroheliograms than the underlying sunspot structure
and must not necessarily possess a counterpart in lower layers. From
the central intensity of Lα above the umbra an electron density of
4.3 × 10<SUP>10</SUP> cm<SUP>-3</SUP> ≲n<SUB>e</SUB><SUP>*</SUP>
≲2.3 × 10<SUP>11</SUP> cm<SUP>-3</SUP> at 20 000 K is estimated.
---------------------------------------------------------
Title: Solar H I LY alpha far wing measurement
Authors: Jouchoux, A.; Vial, J. C.; Artzner, G. E.; Gouttebroze, P.;
Lemaire, P.
1981A&A....93..415J Altcode:
High spectral resolution photoelectric observations of the solar H I
Ly alpha far wing are presented. Measurements above active regions and
quiet sun center are compared to photographic observations of Basri
et al. (1979).
---------------------------------------------------------
Title: On VI (λ = 1032 Å) profiles in and above an active region
prominence, compared to quiet Sun center and limb profiles
Authors: Vial, J. C.; Lemaire, P.; Artzner, G.; Gouttebroze, P.
1980SoPh...68..187V Altcode:
O VI (λ = 1032 Å) profiles have been measured in and above a filament
at the limb, previously analyzed in H I, Mg II, Ca II resonance lines
(Vial et al., 1979). They are compared to profiles measured at the
quiet Sun center and at the quiet Sun limb.
---------------------------------------------------------
Title: Microturbulence near the edge of a solar plage
Authors: Simon, G.; Mouradian, Z.; Dumont, S.; Pecker, J. C.; Artzner,
G.; Vial, J. C.
1980A&A....89L...8S Altcode:
Observations of the Ca II K line at the edge of a solar plage show
enhanced separation of the K2 peaks with respect to the measured value
inside the plage and in the quiet sun. This effect may be interpreted as
a variation of microturbulent motions at the height of formation of K2.
---------------------------------------------------------
Title: Observations of Chromospheric Lines from OSO-8
Authors: Grossmann-Doerth, U.; Kneer, F.; Uexkuell, M.; Artzner,
G. E.; Vial, J. C.
1980SoPh...66....3G Altcode:
The line profiles of Lα, Ca II K and Mg IIk were measured with the
spectrometer of the `Laboratoire de Physique Stellaire et Planétaire'
on board of OSO-8. The results of these measurements are presented.
---------------------------------------------------------
Title: Center-to-limb solar observations of the K<SUB>2</SUB>
component of the Ca II K line with the OSO 8 satellite.
Authors: Dumont, S.; Mouradian, Z.; Pecker, J. -C.; Simon, G.; Artzner,
G. E.; Vial, J. C.
1980CRASB.290..365D Altcode:
OSO 8 spectrometer measurements of the separation between emission
peaks in the K2 Ca II line across the solar disk in quiet and active
regions are presented. The center-to-limb variation in emission peak
separation is found to differ slightly for quiet and facula regions
at distances greater than 0.2 solar radii from the limb, in agreement
with previous observations. For a facula located at the solar limb,
however, the peak separation is observed to be up to 35 percent greater
than in quiet regions, indicating the presence of a region of enhanced
chromospheric turbulence surrounding the faculae.
---------------------------------------------------------
Title: Non thermal velocities in the chromosphere-corona transition
zone of solar active regions.
Authors: Dumont, S.; Mouradian, Z.; Pecker, J. -C.; Chipman, E.;
Artzner, G.; Vial, J. -C.
1980CRASB.290..317D Altcode:
OSO 8 satellite observations of lines of the Si II, Si IV, C IV and
O VI ions in the ultraviolet spectrum of active solar regions are
considered. It is noted that for the case of pronounced physical
dispersion of the data, there is no marked systematic variation from
the center to the edge of the solar disk. The nonthermal velocities
in the transition zone are, for a given temperature, the same as for
quiet regions. In addition, the velocities tend to reach a constant
value at temperatures above 100,000 deg K, and the observed physical
dispersion is much higher than the inaccuracy of the data.
---------------------------------------------------------
Title: Profiles of H I (Lalpha ), Mg II (h and k), Ca II (H and K)
lines of an active filament at the limb, with the LPSP instrument
aboard the OSO-8 satellite.
Authors: Vial, J. C.; Gouttebroze, P.; Artzner, G.; Lemaire, P.
1979SoPh...61...39V Altcode:
We scanned the H I Lα, Mg II h and k, Ca II K and H lines
simultaneously with the LPSP instrument on OSO-8, to investigate the low
and moderate temperature regions of an `active region filament'. The
Lα line is not reversed except for the innermost position in the
prominence. Intensity (k/h), (K/H) ratios are respectively 2 and 1.1,
indicating that the Mg II lines are optically thin, and that Ca II
K is saturated, although not clearly reversed. The results obtained
during the second sequence of observations (K saturated before Lα
for example) indicate that within the size of the slit (1″ × 10″)
we are not observing the same emitting features in the different lines.
---------------------------------------------------------
Title: Profiles of H i (Lyα), MG II (h and K), CA II (h and k)
Lines in an Active Filament at the Limb, Observed with the LPSP
Instrument Onboard the OSO-8 Satellite.
Authors: Vial, J. C.; Gouttebroze, P.; Artzner, G.; Lemaire, P.
1979phsp.coll..250V Altcode: 1979IAUCo..44..250V
No abstract at ADS
---------------------------------------------------------
Title: The Solar H-Lyman-alpha Line
Authors: Artzner, G.
1978A&A....70L..11A Altcode:
Summary A precise measurement of the solar H-Lya 121.6 nm profile
is presented. A preliminary analysis indicates a) a 2.4 1 0.6 km/s
redshift of the solar H-Lya emission over a moderately active region
with respect to the geocoronal absorption ; and b) the presence of
a faint absorption feature, redshif ted 32 km/s with respect to the
geocoronal absorption line. Key words : Lyman-alpha - Solar spectrum -
Chromosphere Downf low - Interstellar hydrogen.
---------------------------------------------------------
Title: The solar hydrogen Lyman-beta and Lyman-alpha lines: disk
center observations from OSO 8 compared with theoretical profiles.
Authors: Gouttebroze, P.; Lemaire, P.; Vial, J. C.; Artzner, G.
1978ApJ...225..655G Altcode:
The solar La and Lfl lines of hydrogen have been measured at the center
of the disk with the LPSP spectrometer aboard OSO 8. These line profiles
are compared with theoretical profiles obtained with different solar
atmospheric models, assuming either complete or partial frequency
redistribution in scattering. The assumption of microturbulence for
the velocity fields appears insufficient to account for the profiles
of the line cores; better results are obtained with a blend of micro-
and macroturbulence, which shows the need of a generalized treatment of
the turbulent motions in the formation of these lines. If the effects
of partial redistribution are taken into account, a good fit of the
line wings requires higher temperatures, in the region under the
plateau, than in the reference atmospheric model of Vernazza, Avrett,
and Loeser. Subject headings: line formation - line profiles - Sun:
chromosphere - Sun: spectra - ultraviolet: spectra
---------------------------------------------------------
Title: Simultaneous time-resolved observations of the H Lalpha ,
Mg k 2795 Å, and Ca K solar lines.
Authors: Artzner, G.; Leibacher, J.; Vial, J. C.; Lemaire, P.;
Gouttebroze, P.
1978ApJ...224L..83A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Calibrated full disk solar H I Lyman-alpha and Lyman-beta
profiles.
Authors: Lemaire, P.; Charra, J.; Jouchoux, A.; Vidal-Madjar, A.;
Artzner, G. E.; Vial, J. C.; Bonnet, R. M.; Skumanich, A.
1978ApJ...223L..55L Altcode:
Resolved solar H I Ly-alpha and -beta profiles have been recorded by the
French LPSP experiment on OSO 8. Intensity observations at the center
and the limb have been combined to obtain flux-equivalent profiles
(5.46 plus or minus 30 percent and 0.078 plus or minus 25 percent
erg/sq cm per sec for Ly-alpha and -beta, respectively). Comparison of
the flux profiles with unresolved calibration rocket profiles allows
one to obtain an absolute calibration.
---------------------------------------------------------
Title: The LPSP instrument on OSO 8. II. In-flight performance and
preliminary results.
Authors: Bonnet, R. M.; Lemaire, P.; Vial, J. C.; Artzner, G.;
Gouttebroze, P.; Jouchoux, A.; Leibacher, J. W.; Skumanich, A.;
Vidal-Madjar, A.
1978ApJ...221.1032B Altcode:
The paper describes the in-flight performance for the first 18 months of
operation of the LPSP (Laboratoire de Physique Stellaire et Planetaire)
instrument incorporated in the OSO 8 launched June 1975. By means of
the instrument, an absolute pointing accuracy of nearly one second
was achieved in orbit during real-time operations. The instrument
uses a Cassegrain telescope and a spectrometer simultaneously
observing six wavelengths. In-flight performance is discussed with
attention to angular resolution, spectral resolution, dispersion
and grating mechanism (spectral scanner) stability, scattered light
background and dark current, photometric standardization, and absolute
calibration. Real-time operation and problems are considered with
reference to pointing system problems, target acquisition, and L-alpha
modulation. Preliminary results involving the observational program,
quiet sun and chromospheric studies, quiet chromospheric oscillation
and transients, sunspots and active regions, prominences, and aeronomy
investigations are reported.
---------------------------------------------------------
Title: Doppler Shifts measured in 0 VI line from OSO-B observations
above and in the vicinity of plage Mc Math 13738.
Authors: Lemaire, P.; Skumanich, A.; Artzner, G.; Gouttebroze, P.;
Vial, J. C.; Bonnet, R. M.; McWhirter, P.
1978BAAS...10Q.440L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: OSO-8 Radio and X-ray observations of the 19 April 1977 flare.
Authors: Skumanich, A.; Jouchoux, A.; Castelli, J.; Lemaire, P.;
Artzner, G.; Gouttebroze, P.; Vial, J. C.; Bonnet, R. M.
1978BAAS...10..441S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: EUV observations of class-C X-ray flare by the LPSP
(Laboratoire de Physique Stellaire et Planétaire du Centre National
de la Recherche Scientifique) spectrometer on OSO-8.
Authors: Jouchoux, A.; Skumanich, A.; Bonnet, R. M.; Lemaire, P.;
Artzner, G.; Leibacher, J.; Vial, J. C.; Vidal-Madjar, A.
1977BAAS....9..432J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The LPSP experiment on OSO-8. I - Instrumentation, description
of operations, laboratory calibrations and pre-launch performances
Authors: Artzner, G.; Bonnet, R. M.; Vial, J. C.; Jouchoux, A.;
Leibacher, J.; Vidal-Madjar, A.; Lemaire, P.
1977SSI.....3..131A Altcode:
The characteristics of OSO-8, including its solar-pointed instrument
assembly and rasters, are discussed, as well as the accompanying
Laboratoire de Physique Stellaire et Planetaire (LPSP) instrumentation,
which is designed to study the solar atmosphere with high spatial,
spectral, and temporal resolution. The LPSP instrument, which consists
of two subassemblies, a Cassegrainian telescope and a spectrometer,
is described; main optical characteristics, including spectral lines
observed, and means of correcting aberrations and eliminating stray
light, are given for the spectrometer. Detectors and their capacities,
and various filter wheel configurations available for detection of
polarized light and discrimination of low orders of diffraction, are
also described. The observation program, which consists of a study of
solar prominences, flares, and dynamic and three-dimensional physical
structures of the chromosphere, as well as determination of seasonal
variations of some gases in earth's atmosphere, is reviewed. A detailed
account of pre-launch tests and calibration procedures is also given.
---------------------------------------------------------
Title: Extreme-Ultraviolet Observations of New Cycle Sunspots with
the LPSP Spectrometer from OSO-8
Authors: Skumanich, A.; Jouchoux, A.; Artzner, G.; Bonnet, R. M.;
Leibacher, J.; Lemaire, P.; Vial, J. C.; Vidal-Madjar, A.
1977BAAS....9..340S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On VI Profiles of Solar Quiet and Active Areas Recorded by
OSO-8 LPSP Experiment".
Authors: Lemaire, P.; Artzner, G.; Vial, J. C.; Bonnet, R. M.;
Gottebroze, P.; Jouchoux, A.; Vidal-Madjar, A.; McWhirter, P.;
Leibacher, J.; Skumainich, A.
1977uxsa.coll...46L Altcode: 1977IAUCo..43...46L
No abstract at ADS
---------------------------------------------------------
Title: OSO-8 Observations of the EUV Chromospheric Network
Authors: Artzner, G.; Bonnet, R. M.; Leibacher, J.; Lemaire, P.;
Skumanich, A.; Vial, J. C.; Vidal-Madjar, A.
1976BAAS....8..332A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar OVI Profiles as Observed by the French Experiment
Aboard OSO-8
Authors: Lemaire, P.; Artzner, G.; Bonnet, R. M.; Vial, F. C.;
Skumanich, A.; Leibacher, J.; Vidal-Madjar, A.
1976BAAS....8R.331L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Evolution of sunspot and active region morphology as observed
on the resonance lines of Ca<SUP>+</SUP> (K, H), Mg<SUP>+</SUP>
(k, h), hydrogen (Lalpha , Lbeta ), and O VI from OSO-8 (LPSP).
Authors: Artzner, G.; Skumanich, A.; Bonnet, R. M.; Vidal-Madjar,
A.; Leibacher, J.; Lemaire, P.; Vial, J. C.
1976BAAS....8..397A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Periodic temporal phenomena in the solar chromosphere as
observed from OSO-8 (LPSP).
Authors: Vial, J. C.; Leibacher, J.; Lemaire, P.; Artzner, G.; Bonnet,
R. M.; Skumanich, A.; Vidal-Madjar, A.
1976BAAS....8..397V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Spatial variations of solar profiles of Ca<SUP>+</SUP> H and
K, Mg<SUP>+</SUP> h and k, and Lyman alpha and beta (H I) resonance
lines as observed from OSO-8 (LPSP).
Authors: Bonnet, R. M.; Artzner, G.; Leibacher, J.; Lemaire, P.;
Skumanich, A.; Vial, J. C.; Vidal-Madjar, A.
1976BAAS....8..397B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Prominence Observations with the OSO-8 French Experiment
Authors: Vial, J. C.; Artzner, G.; Bonnet, R. M.; Lemaire, P.;
Leibacher, J.; Skumanich, A.; Vidalmadjar, A.
1976BAAS....8..344V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: High-Resolution Atmospheric Extinction Measurements from the
French Experiment on Board the NASA Spacecraft OSO-8
Authors: Vidal-Madjar, A.; Roble, R. G.; Mankin, W. G.; Artzner, G.;
Bonnet, R. M.; Lemaire, P.; Vial, J. C.
1976ASSL...61..117V Altcode: 1976aps..conf..117V
No abstract at ADS
---------------------------------------------------------
Title: High resolution atmospheric extinction measurements from the
French experiment on board the NASA spacecraft OSO-8
Authors: Vidal-Madjar, A.; Artzner, G.; Bonnet, R. M.; Lemaire, P.;
Vial, J. C.; Roble, R. G.; Mankin, W. G.
1976atps.proc..117V Altcode:
The French instrument aboard OSO-8 is a multichannel, high-resolution UV
spectrometer for observing very small areas of the sun simultaneously
in the Ca II, Mg II, Lyman alpha, and Lyman beta lines. By observing
extinction through the earth atmosphere, the spectrometer studies the
three-dimensional structure and the composition of the atmosphere. The
quality of data appears to give a 500 m vertical resolution both for
O3 and O2; O3 is observed primarily from 55 to 75 km, while O2 is
observed from 85 to 200 km. Data on the hydrogen absorption present a
new method for evaluating exospheric temperature and atomic hydrogen
density at each point of the exobase.
---------------------------------------------------------
Title: High Resolution Spectroscopy of the Disk Chromosphere. III:
Upward Moving Disturbances as Observed in the Ca II K-Line Wings
Authors: Beckers, J. M.; Artzner, G.
1974SoPh...37..309B Altcode:
We describe the properties of dark structures which are seen in the
K-line wings and which seem to propagate inward into the K-line core,
or upward in the solar atmosphere. These so-called dark whiskers
appear to be related to the bright disturbances (bright whiskers)
described by Liu (1974). Both may be related to the shocks that heat
the chromosphere and corona.