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Author name code: parenti
ADS astronomy entries on 2022-09-14
author:"Parenti, Susanna"
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Title: What drives decayless kink oscillations in active region
coronal loops on the Sun?
Authors: Mandal, Sudip; Chitta, Lakshmi P.; Antolin, Patrick; Peter,
Hardi; Solanki, Sami K.; Auchère, Frédéric; Berghmans, David;
Zhukov, Andrei N.; Teriaca, Luca; Cuadrado, Regina A.; Schühle,
Udo; Parenti, Susanna; Buchlin, Éric; Harra, Louise; Verbeeck, Cis;
Kraaikamp, Emil; Long, David M.; Rodriguez, Luciano; Pelouze, Gabriel;
Schwanitz, Conrad; Barczynski, Krzysztof; Smith, Phil J.
2022arXiv220904251M Altcode:
We study here the phenomena of decayless kink oscillations in a system
of active region (AR) coronal loops. Using high resolution observations
from two different instruments, namely the Extreme Ultraviolet Imager
(EUI) on board Solar Orbiter and the Atmospheric Imaging Assembly
(AIA) on board the Solar Dynamics Observatory, we follow these AR
loops for an hour each on three consecutive days. Our results show
significantly more resolved decayless waves in the higher-resolution
EUI data compared with the AIA data. Furthermore, the same system of
loops exhibits many of these decayless oscillations on Day-2, while on
Day-3, we detect very few oscillations and on Day-1, we find none at
all. Analysis of photospheric magnetic field data reveals that at most
times, these loops were rooted in sunspots, where supergranular flows
are generally absent. This suggests that supergranular flows, which
are often invoked as drivers of decayless waves, are not necessarily
driving such oscillations in our observations. Similarly, our findings
also cast doubt on other possible drivers of these waves, such as a
transient driver or mode conversion of longitudinal waves near the loop
footpoints. In conclusion, through our analysis we find that none of
the commonly suspected sources proposed to drive decayless oscillations
in active region loops seems to be operating in this event and hence,
the search for that elusive wave driver needs to continue.
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Title: The observed large scale equatorial UV corona: new perspectives
with 'recent', 'future' and 'old' data
Authors: Abbo, Lucia; Fineschi, Silvano; Parenti, Susanna; Romoli,
Marco; Pancrazzi, Maurizio; Andretta, Vincenzo; Auchère, Frédéric;
Susino, Roberto; Spadaro, Daniele; Nicolini, Gianalfredo; Giordano,
Silvio; Zangrilli, Luca
2022cosp...44.1327A Altcode:
In order to understand the sources and the physical mechanisms for the
propagation of the Slow Solar Wind (SSW), it is essential to analyze
solar data in the region which shapes the large scale structure in
corona where the SSW is accelerated, such as streamers and boundaries
coronal hole/streamer. The focus of this work is to trace the channels
where the SSW escapes from the solar disk up to 5 solar radii in
corona. We give an overview on how Solar Orbiter observations (remote
sensing and in-situ) together with other space missions (i.e. SPP and
PROBA-3) can give a major contribution to the study of the evolution
of the streamer belt and global corona, of the role of the coronal
magnetic field topology in controlling the solar wind dynamics and
abundance, and of abundance anomalies in streamers and in boundaries
CH/streamer. In particular, we study how to trace back some equatorial
features from the extended corona to the disk. We analyse recent Metis
observations in corona together with the Extreme Ultraviolet Imager
(EUI) observations on disk and corona (by using the occulter). We also
present results from SOHO observations in 1996-1997 (solar minimum),
during which was observed a stable equatorial streamer belt with a
typical dipole magnetic structure. We have analyzed data by UVCS,
SUMER, CDS to trace large scale features and also sub-structures at
very high spatial resolution from the disk up to 3 solar radii. This
comparison and overlapping is still unique in solar physics and it can
improve our knowledge about the origin, acceleration and propagation
of the solar wind.
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Title: Linking the Sun to the Heliosphere Using Composition Data
and Modelling: coronal jets as a test case
Authors: Parenti, Susanna; Giunta, Alessandra
2022cosp...44.2584P Altcode:
Understanding the formation and evolution of the solar wind is still
a priority in the Solar and Heliospheric communities. A real progress
is possible if we improve our understanding of the physical link
between what measured in-situ and its source regions on the Sun. In
this respect, the plasma chemical and charge-state compositions are
considered good diagnostic tools. In this paper we present results from
a work aiming at providing solid diagnostics for linking the in-situ
and the remote sensing measurements. For our test cases, we selected
a period when a single active region produced, close to its sunspot,
jets which had a counterpart signature in the Heliosphere in the
form of type-III radio bursts. This jet therefore marked magnetically
open regions expanding in the heliosphere. We combine solar EUV and
in-situ data together with magnetic field extrapolation, large scale MHD
modeling and FIP (First Ionization Potential) bias modeling to provide
a global picture from the source region of the jet to its possible
signatures at 1AU. Our data analysis reveals the presence of outflow
areas near the jet which are within open magnetic flux regions and
which present FIP bias consistent with the FIP model results. In our
picture, one of these open areas is the candidate jet source. Using a
back-mapping technique we identified the arrival time of this solar
plasma at the ACE spacecraft. The in-situ data show signatures of
changes in the plasma and magnetic field parameters, with FIP bias
consistent with the possible passage of the jet material. Our results
highlight the importance of remote sensing and in-situ coordinated
observations as a key to solve the connectivity problem. We discuss
our results in view of the Solar Orbiter entering the nominal phase,
which is currently providing such unique data in this regard.
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Title: Abundance diagnostics in active regions with Solar
Orbiter/SPICE
Authors: Giunta, Alessandra; Peter, Hardi; Parenti, Susanna; Buchlin,
Eric; Thompson, William; Auchere, Frederic; Kucera, Therese; Carlsson,
Mats; Janvier, Miho; Fludra, Andrzej; Hassler, Donald M.; Grundy,
Timothy; Sidher, Sunil; Guest, Steve; Leeks, Sarah; Fredvik, Terje;
Young, Peter
2022cosp...44.2583G Altcode:
With the launch of Solar Orbiter in February 2020, we are now able to
fully explore the link between the solar activity on the Sun and the
inner heliosphere. Elemental abundance measurements provide a key tracer
to probe the source regions of the solar wind and to track it from the
solar surface and corona to the heliosphere. Abundances of elements
with low first ionisation potential (FIP) are enhanced in the corona
relative to high-FIP elements, with respect to the photosphere. This is
known as the FIP effect, which is measured as abundance bias (FIP bias)
of low and high FIP elements. This effect is vital for understanding the
flow of mass and energy through the solar atmosphere. The comparison
between in-situ and remote sensing composition data, coupled with
modelling, will allow us to trace back the source of heliospheric
plasma. Solar Orbiter has a unique combination of in-situ and remote
sensing instruments that will help to make such a comparison. In
particular, the SPICE (Spectral Imaging of the Coronal Environment)
EUV spectrometer records spectra in two wavelength bands, 70.4-79.0
nm and 97.3-104.9 nm. SPICE is designed to provide spectroheliograms
using a core set of emission lines arising from ions of both low-FIP
and high-FIP elements such as C, N, O, Ne, Mg, S and Fe. These lines
are formed over a wide range of temperatures from 20,000 K to over 1
million K, enabling the analysis of the different layers of the solar
atmosphere. SPICE spectroheliograms can be processed to produce FIP
bias maps, which can be compared to in-situ measurements of the solar
wind composition of the same elements. During the Solar Orbiter Cruise
Phase, SPICE observed several active regions. We will present some of
these observations and discuss the SPICE diagnostic potential to derive
relative abundances (e.g., Mg/Ne) and the FIP bias in those regions.
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Title: Automatic detection of small-scale EUV brightenings observed
by the Solar Orbiter/EUI
Authors: Alipour, N.; Safari, H.; Verbeeck, C.; Berghmans, D.;
Auchère, F.; Chitta, L. P.; Antolin, P.; Barczynski, K.; Buchlin,
É.; Aznar Cuadrado, R.; Dolla, L.; Georgoulis, M. K.; Gissot, S.;
Harra, L.; Katsiyannis, A. C.; Long, D. M.; Mandal, S.; Parenti,
S.; Podladchikova, O.; Petrova, E.; Soubrié, É.; Schühle, U.;
Schwanitz, C.; Teriaca, L.; West, M. J.; Zhukov, A. N.
2022A&A...663A.128A Altcode: 2022arXiv220404027A
Context. Accurate detections of frequent small-scale extreme ultraviolet
(EUV) brightenings are essential to the investigation of the physical
processes heating the corona. <BR /> Aims: We detected small-scale
brightenings, termed campfires, using their morphological and
intensity structures as observed in coronal EUV imaging observations
for statistical analysis. <BR /> Methods: We applied a method based
on Zernike moments and a support vector machine (SVM) classifier
to automatically identify and track campfires observed by Solar
Orbiter/Extreme Ultraviolet Imager (EUI) and Solar Dynamics Observatory
(SDO)/Atmospheric Imaging Assembly (AIA). <BR /> Results: This method
detected 8678 campfires (with length scales between 400 km and 4000 km)
from a sequence of 50 High Resolution EUV telescope (HRI<SUB>EUV</SUB>)
174 Å images. From 21 near co-temporal AIA images covering the same
field of view as EUI, we found 1131 campfires, 58% of which were
also detected in HRI<SUB>EUV</SUB> images. In contrast, about 16%
of campfires recognized in HRI<SUB>EUV</SUB> were detected by AIA. We
obtain a campfire birthrate of 2 × 10<SUP>−16</SUP> m<SUP>−2</SUP>
s<SUP>−1</SUP>. About 40% of campfires show a duration longer than 5
s, having been observed in at least two HRI<SUB>EUV</SUB> images. We
find that 27% of campfires were found in coronal bright points and
the remaining 73% have occurred out of coronal bright points. We
detected 23 EUI campfires with a duration greater than 245 s. We found
that about 80% of campfires are formed at supergranular boundaries,
and the features with the highest total intensities are generated at
network junctions and intense H I Lyman-α emission regions observed
by EUI/HRI<SUB>Lya</SUB>. The probability distribution functions for
the total intensity, peak intensity, and projected area of campfires
follow a power law behavior with absolute indices between 2 and 3. This
self-similar behavior is a possible signature of self-organization,
or even self-organized criticality, in the campfire formation
process. <P />Supplementary material (S1-S3) is available at <A
href="https://www.aanda.org/10.1051/0004-6361/202243257/olm">https://www.aanda.org</A>
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Title: The SPICE spectrograph on Solar Orbiter: an introduction and
results from the first Orbits
Authors: Auchère, Frédéric; Peter, Hardi; Parenti, Susanna; Buchlin,
Eric; Thompson, William; Auchere, Frederic; Teriaca, Luca; Kucera,
Therese; Carlsson, Mats; Janvier, Miho; Fludra, Andrzej; Giunta,
Alessandra; Schuehle, Udo; Hassler, Donald M.; Grundy, Timothy;
Sidher, Sunil; Fredvik, Terje; Plowman, Joseph; Aznar Cuadrado, Regina
2022cosp...44.1338A Altcode:
The Spectral Imaging of the Coronal Environment (SPICE) instrument is
the EUV imaging spectrometer on board the Solar Orbiter mission. With
its ability to derive physical properties of the coronal plasma,
SPICE is a key component of the payload to establish the connection
between the source regions and the in-situ measurements of the solar
wind. The spacecraft was successfully launched in February 2020 and
completed its cruise phase in December 2021. During this period,
the remote sensing instruments were mostly operated during limited
periods of time for 'checkout' engineering activities and synoptic
observations. Nonetheless, several of these periods provided enough
opportunities already to obtain new insights on coronal physics. During
the march 2022 perihelion - close to 0.3 AU - SPICE will provide
its highest spatial resolution data so far. Coordinated observations
between the remote sensing and in-situ instruments will provide the
first opportunity to use the full potential of the Solar Orbiter
mission. We will review the instrument characteristics and present
initial results from the cruise phase and first close encounter.
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Title: Prominence eruption observed in He II 304 Å up to >6
R<SUB>⊙</SUB> by EUI/FSI aboard Solar Orbiter
Authors: Mierla, M.; Zhukov, A. N.; Berghmans, D.; Parenti, S.;
Auchère, F.; Heinzel, P.; Seaton, D. B.; Palmerio, E.; Jejčič, S.;
Janssens, J.; Kraaikamp, E.; Nicula, B.; Long, D. M.; Hayes, L. A.;
Jebaraj, I. C.; Talpeanu, D. -C.; D'Huys, E.; Dolla, L.; Gissot, S.;
Magdalenić, J.; Rodriguez, L.; Shestov, S.; Stegen, K.; Verbeeck,
C.; Sasso, C.; Romoli, M.; Andretta, V.
2022A&A...662L...5M Altcode: 2022arXiv220515214M
<BR /> Aims: We report observations of a unique, large prominence
eruption that was observed in the He II 304 Å passband of the Extreme
Ultraviolet Imager/Full Sun Imager telescope aboard Solar Orbiter on
15-16 February 2022. <BR /> Methods: Observations from several vantage
points - Solar Orbiter, the Solar-Terrestrial Relations Observatory,
the Solar and Heliospheric Observatory, and Earth-orbiting satellites -
were used to measure the kinematics of the erupting prominence and the
associated coronal mass ejection. Three-dimensional reconstruction was
used to calculate the deprojected positions and speeds of different
parts of the prominence. Observations in several passbands allowed us
to analyse the radiative properties of the erupting prominence. <BR />
Results: The leading parts of the erupting prominence and the leading
edge of the corresponding coronal mass ejection propagate at speeds
of around 1700 km s<SUP>−1</SUP> and 2200 km s<SUP>−1</SUP>,
respectively, while the trailing parts of the prominence are
significantly slower (around 500 km s<SUP>−1</SUP>). Parts of the
prominence are tracked up to heights of over 6 R<SUB>⊙</SUB>. The
He II emission is probably produced via collisional excitation rather
than scattering. Surprisingly, the brightness of a trailing feature
increases with height. <BR /> Conclusions: The reported prominence
is the first observed in He II 304 Å emission at such a great
height (above 6 R<SUB>⊙</SUB>). <P />Movies are available at <A
href="https://www.aanda.org/10.1051/0004-6361/202244020/olm">https://www.aanda.org</A>
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Title: Observation of Magnetic Switchback in the Solar Corona
Authors: Telloni, Daniele; Zank, Gary P.; Stangalini, Marco;
Downs, Cooper; Liang, Haoming; Nakanotani, Masaru; Andretta,
Vincenzo; Antonucci, Ester; Sorriso-Valvo, Luca; Adhikari, Laxman;
Zhao, Lingling; Marino, Raffaele; Susino, Roberto; Grimani, Catia;
Fabi, Michele; D'Amicis, Raffaella; Perrone, Denise; Bruno, Roberto;
Carbone, Francesco; Mancuso, Salvatore; Romoli, Marco; Da Deppo, Vania;
Fineschi, Silvano; Heinzel, Petr; Moses, John D.; Naletto, Giampiero;
Nicolini, Gianalfredo; Spadaro, Daniele; Teriaca, Luca; Frassati,
Federica; Jerse, Giovanna; Landini, Federico; Pancrazzi, Maurizio;
Russano, Giuliana; Sasso, Clementina; Berghmans, David; Auchère,
Frédéric; Aznar Cuadrado, Regina; Chitta, Lakshmi P.; Harra, Louise;
Kraaikamp, Emil; Long, David M.; Mandal, Sudip; Parenti, Susanna;
Pelouze, Gabriel; Peter, Hardi; Rodriguez, Luciano; Schühle, Udo;
Schwanitz, Conrad; Smith, Phil J.; Verbeeck, Cis; Zhukov, Andrei N.
2022arXiv220603090T Altcode:
Switchbacks are sudden, large radial deflections of the solar wind
magnetic field, widely revealed in interplanetary space by the Parker
Solar Probe. The switchbacks' formation mechanism and sources are still
unresolved, although candidate mechanisms include Alfvénic turbulence,
shear-driven Kelvin-Helmholtz instabilities, interchange reconnection,
and geometrical effects related to the Parker spiral. This Letter
presents observations from the Metis coronagraph onboard Solar Orbiter
of a single large propagating S-shaped vortex, interpreted as first
evidence of a switchback in the solar corona. It originated above
an active region with the related loop system bounded by open-field
regions to the East and West. Observations, modeling, and theory provide
strong arguments in favor of the interchange reconnection origin of
switchbacks. Metis measurements suggest that the initiation of the
switchback may also be an indicator of the origin of slow solar wind.
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Title: Validation of a Wave Heated 3D MHD Coronal-wind Model using
Polarized Brightness and EUV Observations
Authors: Parenti, Susanna; Réville, Victor; Brun, Allan Sacha;
Pinto, Rui F.; Auchère, Frédéric; Buchlin, Éric; Perri, Barbara;
Strugarek, Antoine
2022ApJ...929...75P Altcode: 2022arXiv220310876P
The physical properties responsible for the formation and evolution
of the corona and heliosphere are still not completely understood. 3D
MHD global modeling is a powerful tool to investigate all the possible
candidate processes. To fully understand the role of each of them,
we need a validation process where the output from the simulations
is quantitatively compared to the observational data. In this work,
we present the results from our validation process applied to the
wave turbulence driven 3D MHD corona-wind model WindPredict-AW. At
this stage of the model development, we focus the work to the coronal
regime in quiescent condition. We analyze three simulation results,
which differ by the boundary values. We use the 3D distributions of
density and temperature, output from the simulations at the time of
around the first Parker Solar Probe perihelion (during minimum of
the solar activity), to synthesize both extreme ultraviolet (EUV)
and white-light-polarized (WL pB) images to reproduce the observed
solar corona. For these tests, we selected AIA 193 Å, 211 Å, and
171 Å EUV emissions, MLSO K-Cor, and LASCO C2 pB images obtained on
2018 November 6 and 7. We then make quantitative comparisons of the
disk and off limb corona. We show that our model is able to produce
synthetic images comparable to those of the observed corona.
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Title: Flux rope and dynamics of the heliospheric current sheet. Study
of the Parker Solar Probe and Solar Orbiter conjunction of June 2020
Authors: Réville, V.; Fargette, N.; Rouillard, A. P.; Lavraud,
B.; Velli, M.; Strugarek, A.; Parenti, S.; Brun, A. S.; Shi, C.;
Kouloumvakos, A.; Poirier, N.; Pinto, R. F.; Louarn, P.; Fedorov,
A.; Owen, C. J.; Génot, V.; Horbury, T. S.; Laker, R.; O'Brien, H.;
Angelini, V.; Fauchon-Jones, E.; Kasper, J. C.
2022A&A...659A.110R Altcode: 2021arXiv211207445R
Context. Solar Orbiter and Parker Solar Probe jointly observed the
solar wind for the first time in June 2020, capturing data from very
different solar wind streams: calm, Alfvénic wind and also highly
dynamic large-scale structures. Context. Our aim is to understand the
origin and characteristics of the highly dynamic solar wind observed by
the two probes, particularly in the vicinity of the heliospheric current
sheet (HCS). <BR /> Methods: We analyzed the plasma data obtained
by Parker Solar Probe and Solar Orbiter in situ during the month of
June 2020. We used the Alfvén-wave turbulence magnetohydrodynamic
solar wind model WindPredict-AW and we performed two 3D simulations
based on ADAPT solar magnetograms for this period. <BR /> Results:
We show that the dynamic regions measured by both spacecraft are
pervaded by flux ropes close to the HCS. These flux ropes are also
present in the simulations, forming at the tip of helmet streamers,
that is, at the base of the heliospheric current sheet. The formation
mechanism involves a pressure-driven instability followed by a fast
tearing reconnection process. We further characterize the 3D spatial
structure of helmet streamer born flux ropes, which appears in the
simulations to be related to the network of quasi-separatrices.
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Title: Stereoscopy of extreme UV quiet Sun brightenings observed by
Solar Orbiter/EUI
Authors: Zhukov, A. N.; Mierla, M.; Auchère, F.; Gissot, S.;
Rodriguez, L.; Soubrié, E.; Thompson, W. T.; Inhester, B.; Nicula, B.;
Antolin, P.; Parenti, S.; Buchlin, É.; Barczynski, K.; Verbeeck, C.;
Kraaikamp, E.; Smith, P. J.; Stegen, K.; Dolla, L.; Harra, L.; Long,
D. M.; Schühle, U.; Podladchikova, O.; Aznar Cuadrado, R.; Teriaca,
L.; Haberreiter, M.; Katsiyannis, A. C.; Rochus, P.; Halain, J. -P.;
Jacques, L.; Berghmans, D.
2021A&A...656A..35Z Altcode: 2021arXiv210902169Z
Context. The three-dimensional fine structure of the solar atmosphere
is still not fully understood as most of the available observations
are taken from a single vantage point. <BR /> Aims: The goal of the
paper is to study the three-dimensional distribution of the small-scale
brightening events ("campfires") discovered in the extreme-UV quiet Sun
by the Extreme Ultraviolet Imager (EUI) aboard Solar Orbiter. <BR />
Methods: We used a first commissioning data set acquired by the EUI's
High Resolution EUV telescope on 30 May 2020 in the 174 Å passband and
we combined it with simultaneous data taken by the Atmospheric Imaging
Assembly (AIA) aboard the Solar Dynamics Observatory in a similar 171
Å passband. The two-pixel spatial resolution of the two telescopes
is 400 km and 880 km, respectively, which is sufficient to identify
the campfires in both data sets. The two spacecraft had an angular
separation of around 31.5° (essentially in heliographic longitude),
which allowed for the three-dimensional reconstruction of the campfire
position. These observations represent the first time that stereoscopy
was achieved for brightenings at such a small scale. Manual and
automatic triangulation methods were used to characterize the campfire
data. <BR /> Results: The height of the campfires is located between
1000 km and 5000 km above the photosphere and we find a good agreement
between the manual and automatic methods. The internal structure of
campfires is mostly unresolved by AIA; however, for a particularly
large campfire, we were able to triangulate a few pixels, which are
all in a narrow range between 2500 and 4500 km. <BR /> Conclusions: We
conclude that the low height of EUI campfires suggests that they belong
to the previously unresolved fine structure of the transition region and
low corona of the quiet Sun. They are probably apexes of small-scale
dynamic loops heated internally to coronal temperatures. This work
demonstrates that high-resolution stereoscopy of structures in the
solar atmosphere has become feasible.
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Title: Adding a transition region in global MHD models of the
solar corona
Authors: Réville, V.; Parenti, S.; Brun, A. S.; Strugarek, A.;
Rouillard, A. P.; Velli, M.; Perri, B.; Pinto, R. F.
2021sf2a.conf..230R Altcode:
Global MHD simulations of the solar corona are an essential tool
to investigate long standing problems, such as finding the source
of coronal heating and the mechanisms responsible for the onset and
propagation of coronal mass ejections. The very low atmospheric layers
of the corona, are however, very difficult to model as they imply very
steep gradients of density and temperature over only a few thousand
kilometers. In this proceedings, we illustrate some of the benefits
of including a very simple transition region in global MHD models and
the differences in the plasma properties, comparing with in situ data
of the Parker Solar Probe.
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Title: Full Vector Velocity Reconstruction Using Solar Orbiter
Doppler Map Observations.
Authors: Podladchikova, Olena; Harra, Louise; Barczynski, Krzysztof;
Mandrini, Cristina; Auchere, F.; Berghmans, David; Buchlin, Eric;
Dolla, Laurent; Mierla, Marilena; Parenti, Susanna; Rodriguez, Luciano
2021AGUFMNG35B0432P Altcode:
The Solar Orbiter mission opens up opportunities forthe
combined analysis of measurements obtained by solar imagers and
spectrometers. For the first time, different space spectrometerswill
be located at wide angles to each other, allowing three-dimensional
(3D) spectroscopy of the solar atmosphere.The aim of this work is to
prepare the methodology to facilitate the reconstruction of 3D vector
velocities from two stereoscopicLOS Doppler velocity measurements using
the Spectral Imaging of the Coronal Environment (SPICE) on board the
Solar Orbiter andthe near-Earth spectrometers, while widely separated in
space. We develop the methodology using the libraries designed earlier
for the STEREO mission but applied to spectroscopicdata from the Hinode
mission and the Solar Dynamics Observatory. We use well-known methods
of static and dynamic solar rotationstereoscopy and the methods of
EUV stereoscopic triangulation for optically-thin coronal EUV plasma
emissions. We develop new algorithms using analytical geometry in
space to determine the 3D velocity in coronal loops. We demonstrate
our approach with the reconstruction of 3D velocity vectors in plasma
flows along "open" and "closed"magnetic loops. This technique will be
applied first to an actual situation of two spacecraft at different
separations with spectrometers onboard (SPICE versus the Interface
Region Imaging Spectrograph (IRIS) and Hinode imaging spectrometer)
during the Solar Orbiternominal phase. We summarise how these
observations can be coordinated.
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Title: Stereoscopy of extreme UV quiet Sun brightenings observed by
Solar Orbiter/EUI
Authors: Zhukov, Andrei; Mierla, Marilena; Auchere, F.; Gissot,
Samuel; Rodriguez, Luciano; Soubrie, Elie; Thompson, William; Inhester,
Bernd; Nicula, Bogdan; Antolin, Patrick; Parenti, Susanna; Buchlin,
Eric; Barczynski, Krzysztof; Verbeeck, Cis; Kraaikamp, Emil; Smith,
Philip; Stegen, Koen; Dolla, Laurent; Harra, Louise; Long, David;
Schuhle, Udo; Podladchikova, Olena; Aznar Cuadrado, Regina; Teriaca,
Luca; Haberreiter, Margit; Katsiyannis, Athanassios; Rochus, Pierre;
Halain, Jean-Philippe; Jacques, Lionel; Berghmans, David
2021AGUFMSH21A..03Z Altcode:
We study the three-dimensional distribution of small-scale brightening
events (campfires) discovered in the extreme-ultraviolet (EUV) quiet Sun
by the EUI telescope onboard the Solar Orbiter mission. We use one of
the first commissioning data sets acquired by the HRI_EUV telescope of
EUI on 2020 May 30 in the 174 A passband, combined with the simultaneous
SDO/AIA dataset taken in the very similar 171 A passband. The spatial
resolution of the two telescopes is sufficient to identify the campfires
in both datasets. The angular separation between the two spacecraft of
around 31.5 degrees allowed for the three-dimensional reconstruction
of the position of campfires. This is the first time that stereoscopy
was achieved for structures at such a small scale. Manual and automatic
triangulation methods were used. The height of campfires is between 1000
km and 5000 km above the photosphere, and there is a good agreement
between the results of manual and automatic methods. The internal
structure of campfires is mostly not resolved by AIA, but for a large
campfire we could triangulate a few pixels, which are all in a narrow
height range between 2500 and 4500 km. The low height of campfires
suggests that they belong to the previously unresolved fine structure
of the transition region and low corona of the quiet Sun. They are
probably apexes of small-scale dynamic loops internally heated to
coronal temperatures. This work demonstrates that high-resolution
stereoscopy of structures in the solar atmosphere has become possible.
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Title: Extreme-UV quiet Sun brightenings observed by the Solar
Orbiter/EUI
Authors: Berghmans, D.; Auchère, F.; Long, D. M.; Soubrié, E.;
Mierla, M.; Zhukov, A. N.; Schühle, U.; Antolin, P.; Harra, L.;
Parenti, S.; Podladchikova, O.; Aznar Cuadrado, R.; Buchlin, É.;
Dolla, L.; Verbeeck, C.; Gissot, S.; Teriaca, L.; Haberreiter, M.;
Katsiyannis, A. C.; Rodriguez, L.; Kraaikamp, E.; Smith, P. J.;
Stegen, K.; Rochus, P.; Halain, J. P.; Jacques, L.; Thompson, W. T.;
Inhester, B.
2021A&A...656L...4B Altcode: 2021arXiv210403382B
Context. The heating of the solar corona by small heating events
requires an increasing number of such events at progressively smaller
scales, with the bulk of the heating occurring at scales that are
currently unresolved. <BR /> Aims: The goal of this work is to study the
smallest brightening events observed in the extreme-UV quiet Sun. <BR />
Methods: We used commissioning data taken by the Extreme Ultraviolet
Imager (EUI) on board the recently launched Solar Orbiter mission. On
30 May 2020, the EUI was situated at 0.556 AU from the Sun. Its
High Resolution EUV telescope (HRI<SUB>EUV</SUB>, 17.4 nm passband)
reached an exceptionally high two-pixel spatial resolution of 400
km. The size and duration of small-scale structures was determined
by the HRI<SUB>EUV</SUB> data, while their height was estimated
from triangulation with simultaneous images from the Atmospheric
Imaging Assembly (AIA) on board the Solar Dynamics Observatory
mission. This is the first stereoscopy of small-scale brightenings
at high resolution. <BR /> Results: We observed small localised
brightenings, also known as `campfires', in a quiet Sun region with
length scales between 400 km and 4000 km and durations between 10 s and
200 s. The smallest and weakest of these HRI<SUB>EUV</SUB> brightenings
have not been previously observed. Simultaneous observations from the
EUI High-resolution Lyman-α telescope (HRI<SUB>Lya</SUB>) do not show
localised brightening events, but the locations of the HRI<SUB>EUV</SUB>
events clearly correspond to the chromospheric network. Comparisons with
simultaneous AIA images shows that most events can also be identified
in the 17.1 nm, 19.3 nm, 21.1 nm, and 30.4 nm pass-bands of AIA,
although they appear weaker and blurred. Our differential emission
measure analysis indicated coronal temperatures peaking at log T ≈
6.1 − 6.15. We determined the height for a few of these campfires to
be between 1000 and 5000 km above the photosphere. <BR /> Conclusions:
We find that `campfires' are mostly coronal in nature and rooted in the
magnetic flux concentrations of the chromospheric network. We interpret
these events as a new extension to the flare-microflare-nanoflare
family. Given their low height, the EUI `campfires' could stand as a
new element of the fine structure of the transition region-low corona,
that is, as apexes of small-scale loops that undergo internal heating
all the way up to coronal temperatures.
---------------------------------------------------------
Title: First observations from the SPICE EUV spectrometer on Solar
Orbiter
Authors: Fludra, A.; Caldwell, M.; Giunta, A.; Grundy, T.; Guest,
S.; Leeks, S.; Sidher, S.; Auchère, F.; Carlsson, M.; Hassler, D.;
Peter, H.; Aznar Cuadrado, R.; Buchlin, É.; Caminade, S.; DeForest,
C.; Fredvik, T.; Haberreiter, M.; Harra, L.; Janvier, M.; Kucera, T.;
Müller, D.; Parenti, S.; Schmutz, W.; Schühle, U.; Solanki, S. K.;
Teriaca, L.; Thompson, W. T.; Tustain, S.; Williams, D.; Young, P. R.;
Chitta, L. P.
2021A&A...656A..38F Altcode: 2021arXiv211011252F
<BR /> Aims: We present first science observations taken during the
commissioning activities of the Spectral Imaging of the Coronal
Environment (SPICE) instrument on the ESA/NASA Solar Orbiter
mission. SPICE is a high-resolution imaging spectrometer operating at
extreme ultraviolet (EUV) wavelengths. In this paper we illustrate
the possible types of observations to give prospective users a
better understanding of the science capabilities of SPICE. <BR />
Methods: We have reviewed the data obtained by SPICE between April
and June 2020 and selected representative results obtained with
different slits and a range of exposure times between 5 s and 180
s. Standard instrumental corrections have been applied to the raw
data. <BR /> Results: The paper discusses the first observations
of the Sun on different targets and presents an example of the full
spectra from the quiet Sun, identifying over 40 spectral lines from
neutral hydrogen and ions of carbon, oxygen, nitrogen, neon, sulphur,
magnesium, and iron. These lines cover the temperature range between
20 000 K and 1 million K (10 MK in flares), providing slices of the
Sun's atmosphere in narrow temperature intervals. We provide a list
of count rates for the 23 brightest spectral lines. We show examples
of raster images of the quiet Sun in several strong transition region
lines, where we have found unusually bright, compact structures in the
quiet Sun network, with extreme intensities up to 25 times greater
than the average intensity across the image. The lifetimes of these
structures can exceed 2.5 hours. We identify them as a transition
region signature of coronal bright points and compare their areas and
intensity enhancements. We also show the first above-limb measurements
with SPICE above the polar limb in C III, O VI, and Ne VIII lines, and
far off limb measurements in the equatorial plane in Mg IX, Ne VIII,
and O VI lines. We discuss the potential to use abundance diagnostics
methods to study the variability of the elemental composition that can
be compared with in situ measurements to help confirm the magnetic
connection between the spacecraft location and the Sun's surface,
and locate the sources of the solar wind. <BR /> Conclusions: The
SPICE instrument successfully performs measurements of EUV spectra
and raster images that will make vital contributions to the scientific
success of the Solar Orbiter mission.
---------------------------------------------------------
Title: Linking the Sun to the Heliosphere Using Composition Data
and Modelling
Authors: Parenti, Susanna; Chifu, Iulia; Del Zanna, Giulio; Edmondson,
Justin; Giunta, Alessandra; Hansteen, Viggo H.; Higginson, Aleida;
Laming, J. Martin; Lepri, Susan T.; Lynch, Benjamin J.; Rivera, Yeimy
J.; von Steiger, Rudolf; Wiegelmann, Thomas; Wimmer-Schweingruber,
Robert F.; Zambrana Prado, Natalia; Pelouze, Gabriel
2021SSRv..217...78P Altcode: 2021arXiv211006111P
Our understanding of the formation and evolution of the corona and
the heliosphere is linked to our capability of properly interpret the
data from remote sensing and in-situ observations. In this respect,
being able to correctly connect in-situ observations with their source
regions on the Sun is the key for solving this problem. In this work
we aim at testing a diagnostics method for this connectivity.
---------------------------------------------------------
Title: Stereoscopic measurements of coronal Doppler velocities
Authors: Podladchikova, O.; Harra, L.; Barczynski, K.; Mandrini,
C. H.; Auchère, F.; Berghmans, D.; Buchlin, É.; Dolla, L.; Mierla,
M.; Parenti, S.; Rodriguez, L.
2021A&A...655A..57P Altcode: 2021arXiv210802280P
Context. The Solar Orbiter mission, with an orbit outside the Sun-Earth
line and leaving the ecliptic plane, opens up opportunities for
the combined analysis of measurements obtained by solar imagers and
spectrometers. For the first time different space spectrometers will be
located at wide angles to each other, allowing three-dimensional (3D)
spectroscopy of the solar atmosphere. <BR /> Aims: The aim of this
work is to prepare a methodology to facilitate the reconstruction
of 3D vector velocities from two stereoscopic line of sight (LOS)
Doppler velocity measurements using the Spectral Imaging of the
Coronal Environment (SPICE) on board the Solar Orbiter and the
near-Earth spectrometers, while widely separated in space. <BR />
Methods: We developed the methodology using the libraries designed
earlier for the STEREO mission, but applied to spectroscopic data
from the Hinode mission and the Solar Dynamics Observatory. We used
well-known methods of static and dynamic solar rotation stereoscopy and
the methods of extreme ultraviolet (EUV) stereoscopic triangulation
for optically thin coronal EUV plasma emissions. We developed new
algorithms using analytical geometry in space to determine the 3D
velocity in coronal loops. <BR /> Results: We demonstrate our approach
with the reconstruction of 3D velocity vectors in plasma flows along
`open' and `closed' magnetic loops. This technique will be applied
to an actual situation of two spacecraft at different separations
with spectrometers on board during the Solar Orbiter nominal phase:
SPICE versus the Interface Region Imaging Spectrograph (IRIS) and
Hinode imaging spectrometer. We summarise how these observations can
be coordinated. <P />Movies associated to Fig. 1 are available at <A
href="https://www.aanda.org/10.1051/0004-6361/202140457/olm">https://www.aanda.org</A>
---------------------------------------------------------
Title: Magnetic imaging of the outer solar atmosphere (MImOSA)
Authors: Peter, H.; Ballester, E. Alsina; Andretta, V.; Auchère, F.;
Belluzzi, L.; Bemporad, A.; Berghmans, D.; Buchlin, E.; Calcines, A.;
Chitta, L. P.; Dalmasse, K.; Alemán, T. del Pino; Feller, A.; Froment,
C.; Harrison, R.; Janvier, M.; Matthews, S.; Parenti, S.; Przybylski,
D.; Solanki, S. K.; Štěpán, J.; Teriaca, L.; Bueno, J. Trujillo
2021ExA...tmp...95P Altcode:
The magnetic activity of the Sun directly impacts the Earth and human
life. Likewise, other stars will have an impact on the habitability of
planets orbiting these host stars. Although the magnetic field at the
surface of the Sun is reasonably well characterised by observations,
the information on the magnetic field in the higher atmospheric layers
is mainly indirect. This lack of information hampers our progress in
understanding solar magnetic activity. Overcoming this limitation would
allow us to address four paramount long-standing questions: (1) How
does the magnetic field couple the different layers of the atmosphere,
and how does it transport energy? (2) How does the magnetic field
structure, drive and interact with the plasma in the chromosphere and
upper atmosphere? (3) How does the magnetic field destabilise the outer
solar atmosphere and thus affect the interplanetary environment? (4)
How do magnetic processes accelerate particles to high energies? New
ground-breaking observations are needed to address these science
questions. We suggest a suite of three instruments that far exceed
current capabilities in terms of spatial resolution, light-gathering
power, and polarimetric performance: (a) A large-aperture UV-to-IR
telescope of the 1-3 m class aimed mainly to measure the magnetic
field in the chromosphere by combining high spatial resolution
and high sensitivity. (b) An extreme-UV-to-IR coronagraph that is
designed to measure the large-scale magnetic field in the corona with
an aperture of about 40 cm. (c) An extreme-UV imaging polarimeter
based on a 30 cm telescope that combines high throughput in the
extreme UV with polarimetry to connect the magnetic measurements
of the other two instruments. Placed in a near-Earth orbit, the data
downlink would be maximised, while a location at L4 or L5 would provide
stereoscopic observations of the Sun in combination with Earth-based
observatories. This mission to measure the magnetic field will finally
unlock the driver of the dynamics in the outer solar atmosphere and
thereby will greatly advance our understanding of the Sun and the
heliosphere.
---------------------------------------------------------
Title: Vector Velocities Measurements with the Solar Orbiter SPICE
Spectrometer
Authors: Podladchikova, O.; Harra, L.; Barczynski, K.; Mandrini,
C.; Auchère, F.; Berghmans, D.; Buchlin, E.; Dolla, L.; Mierla, M.;
Parenti, S.; Rodriguez, L.
2021AAS...23831312P Altcode:
The Solar Orbiter mission, with an orbit outside the Sun-Earth
line and leaving the ecliptic plane, opens up opportunities for
the combined analysis of measurements obtained by solar imagers and
spectrometers. For the first time, different spectrometers will be
located at wide angles to each other, allowing three-dimensional (3D)
spectroscopy of the solar atmosphere. Here we develop a methodology to
prepare for this kind of analysis, by using data from the Hinode mission
and the Solar Dynamics Observatory, respectively. We employ solar
rotation to simulate measurements of spectrometers with different views
of the solar corona. The resulting data allow us to apply stereoscopic
tie-pointing and triangulation techniques designed for the STEREO
spacecraft pair, and to perform 3D analysis of the Doppler shifts of
a quasi-stationary active region. Our approach allows the accurate
reconstruction of 3D velocity vectors in plasma flows along "open" and
"closed" magnetic loops. This technique will be applied to the actual
situation of two spacecraft at different separations with spectrometers
on board (the Solar Orbiter Spectral Imaging of the Coronal Environment
versus the Interface Region Imaging Spectrograph (IRIS) and Hinode
imaging spectrometer) and we summarise how these observations can be
coordinated to assess vector velocity measurements. This 3D spectroscopy
method will facilitate the understanding of the complex flows that
take place throughout the solar atmosphere.
---------------------------------------------------------
Title: The Heating of the Solar Corona
Authors: Viall, Nicholeen M.; De Moortel, Ineke; Downs, Cooper;
Klimchuk, James A.; Parenti, Susanna; Reale, Fabio
2021GMS...258...35V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Critical Science Plan for the Daniel K. Inouye Solar Telescope
(DKIST)
Authors: Rast, Mark P.; Bello González, Nazaret; Bellot Rubio,
Luis; Cao, Wenda; Cauzzi, Gianna; Deluca, Edward; de Pontieu, Bart;
Fletcher, Lyndsay; Gibson, Sarah E.; Judge, Philip G.; Katsukawa,
Yukio; Kazachenko, Maria D.; Khomenko, Elena; Landi, Enrico; Martínez
Pillet, Valentín; Petrie, Gordon J. D.; Qiu, Jiong; Rachmeler,
Laurel A.; Rempel, Matthias; Schmidt, Wolfgang; Scullion, Eamon; Sun,
Xudong; Welsch, Brian T.; Andretta, Vincenzo; Antolin, Patrick; Ayres,
Thomas R.; Balasubramaniam, K. S.; Ballai, Istvan; Berger, Thomas E.;
Bradshaw, Stephen J.; Campbell, Ryan J.; Carlsson, Mats; Casini,
Roberto; Centeno, Rebecca; Cranmer, Steven R.; Criscuoli, Serena;
Deforest, Craig; Deng, Yuanyong; Erdélyi, Robertus; Fedun, Viktor;
Fischer, Catherine E.; González Manrique, Sergio J.; Hahn, Michael;
Harra, Louise; Henriques, Vasco M. J.; Hurlburt, Neal E.; Jaeggli,
Sarah; Jafarzadeh, Shahin; Jain, Rekha; Jefferies, Stuart M.; Keys,
Peter H.; Kowalski, Adam F.; Kuckein, Christoph; Kuhn, Jeffrey R.;
Kuridze, David; Liu, Jiajia; Liu, Wei; Longcope, Dana; Mathioudakis,
Mihalis; McAteer, R. T. James; McIntosh, Scott W.; McKenzie, David
E.; Miralles, Mari Paz; Morton, Richard J.; Muglach, Karin; Nelson,
Chris J.; Panesar, Navdeep K.; Parenti, Susanna; Parnell, Clare E.;
Poduval, Bala; Reardon, Kevin P.; Reep, Jeffrey W.; Schad, Thomas A.;
Schmit, Donald; Sharma, Rahul; Socas-Navarro, Hector; Srivastava,
Abhishek K.; Sterling, Alphonse C.; Suematsu, Yoshinori; Tarr, Lucas
A.; Tiwari, Sanjiv; Tritschler, Alexandra; Verth, Gary; Vourlidas,
Angelos; Wang, Haimin; Wang, Yi-Ming; NSO and DKIST Project; DKIST
Instrument Scientists; DKIST Science Working Group; DKIST Critical
Science Plan Community
2021SoPh..296...70R Altcode: 2020arXiv200808203R
The National Science Foundation's Daniel K. Inouye Solar Telescope
(DKIST) will revolutionize our ability to measure, understand,
and model the basic physical processes that control the structure
and dynamics of the Sun and its atmosphere. The first-light DKIST
images, released publicly on 29 January 2020, only hint at the
extraordinary capabilities that will accompany full commissioning of
the five facility instruments. With this Critical Science Plan (CSP)
we attempt to anticipate some of what those capabilities will enable,
providing a snapshot of some of the scientific pursuits that the DKIST
hopes to engage as start-of-operations nears. The work builds on the
combined contributions of the DKIST Science Working Group (SWG) and
CSP Community members, who generously shared their experiences, plans,
knowledge, and dreams. Discussion is primarily focused on those issues
to which DKIST will uniquely contribute.
---------------------------------------------------------
Title: Stereoscopic Measurements of Coronal Doppler Velocities aboard
Solar Orbiter
Authors: Podladchikova, Olena; Harra, Louise K.; Mandrini, Cristina
H.; Rodriguez, Luciano; Parenti, Susanna; Dolla, Laurent; Buchlin,
Eric; Auchere, Frederic; Mierla, Marilena; Barczynski, Krzysztof
2021cosp...43E.957P Altcode:
The Solar Orbiter mission, whose orbit is outside the Sun-Earth
line, opens up novel opportunities for the combined analysis of
measurements by solar imagers and spectrometers. For the first time
different spectrometers will be located at wide angles with each
other allowing 3D spectroscopy in the solar atmosphere. In order
to develop a methodology for these opportunities we make use of the
Hinode EUV Imaging Spectrometer (EIS) and Atmospheric Imaging Assembly
(AIA) on the Solar Dynamics Observatory (SDO) and by employing solar
rotation we simulate the measurements of spectrometers that have
different views of solar corona. The resulting data allows us to apply
stereoscopic tie-pointing and triangulation techniques designed for
SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation)
imaging suite on the STEREO (Solar Terrestrial Relations Observatory)
spacecraft pair and perform three-dimensional analysis of Doppler shifts
of quasi-stationary active region.We present a technique that allows
the accurate reconstruction of the 3D velocity vector in plasma flows
along open and closed magnetic loops. This technique will be applied
to the real situation of two spacecraft at different separations with
spectrometers onboard. This will include the Solar Orbiter Spectral
Imaging of the Coronal Environment (SPICE), the Solar Orbiter Extreme
Ultraviolet Imager (EUI), the Interface Region Imaging Spectrograph
(IRIS) and Hinode EIS spectrometers and we summarise how these can be
coordinated. This 3D spectroscopy is a new research domain that will
aid the understanding of the complex flows that take place throughout
the solar atmosphere.
---------------------------------------------------------
Title: Expected science from the Solar Orbiter Remote Sensing
instruments
Authors: Parenti, Susanna
2021cosp...43E.948P Altcode:
Solar Orbiter payload consists of a ten instruments, six of which for
remote sensing observations. The mission has a unique profile with
the main properties of being deep, with orbits varying uniquely in
latitudes and solar distance. These aspects produce limits in the
telemetry rate, which vary greatly along each orbit, posing great
challenge for the remote sensing instruments. In this context, the
instrument teams and ESA-NASA have been working together incessantly
to prepare the operations for optimizing the instruments performances
and thus maximize the science return from this complementarity and
comprehensive remote sensing payload. In this talk I will summarize
the mission profile and the remote sensing instruments observational
characteristics. These will serve to discuss the science opportunities
to provide a new view of our star, from its interior to the corona
and solar wind. Observations during recurrent unique configurations
of Solar Orbiter with other Earth and space observatories will be used
to obtain both contextual and multi-point of view data, providing the
first ever data of such a kind. I will also present some of the first
data obtained during Commissioning in 2020 which already anticipate
significant novelties.
---------------------------------------------------------
Title: Magnetic Imaging of the Outer Solar Atmosphere (MImOSA):
Unlocking the driver of the dynamics in the upper solar atmosphere
Authors: Peter, H.; Alsina Ballester, E.; Andretta, V.; Auchere, F.;
Belluzzi, L.; Bemporad, A.; Berghmans, D.; Buchlin, E.; Calcines, A.;
Chitta, L. P.; Dalmasse, K.; del Pino Aleman, T.; Feller, A.; Froment,
C.; Harrison, R.; Janvier, M.; Matthews, S.; Parenti, S.; Przybylski,
D.; Solanki, S. K.; Stepan, J.; Teriaca, L.; Trujillo Bueno, J.
2021arXiv210101566P Altcode:
The magnetic activity of the Sun directly impacts the Earth and human
life. Likewise, other stars will have an impact on the habitability
of planets orbiting these host stars. The lack of information on the
magnetic field in the higher atmospheric layers hampers our progress in
understanding solar magnetic activity. Overcoming this limitation would
allow us to address four paramount long-standing questions: (1) How
does the magnetic field couple the different layers of the atmosphere,
and how does it transport energy? (2) How does the magnetic field
structure, drive and interact with the plasma in the chromosphere and
upper atmosphere? (3) How does the magnetic field destabilise the outer
solar atmosphere and thus affect the interplanetary environment? (4)
How do magnetic processes accelerate particles to high energies? New
ground-breaking observations are needed to address these science
questions. We suggest a suite of three instruments that far exceed
current capabilities in terms of spatial resolution, light-gathering
power, and polarimetric performance: (a) A large-aperture UV-to-IR
telescope of the 1-3 m class aimed mainly to measure the magnetic
field in the chromosphere by combining high spatial resolution and high
sensitivity. (b) An extreme-UV-to-IR coronagraph that is designed to
measure the large-scale magnetic field in the corona with an aperture
of about 40 cm. (c) An extreme-UV imaging polarimeter based on a 30
cm telescope that combines high throughput in the extreme UV with
polarimetry to connect the magnetic measurements of the other two
instruments. This mission to measure the magnetic field will unlock
the driver of the dynamics in the outer solar atmosphere and thereby
greatly advance our understanding of the Sun and the heliosphere.
---------------------------------------------------------
Title: Relative coronal abundance diagnostics with Solar Orbiter/SPICE
Authors: Zambrana Prado, N.; Buchlin, E.; Peter, H.; Young, P. R.;
Auchere, F.; Carlsson, M.; Fludra, A.; Hassler, D.; Aznar Cuadrado,
R.; Caminade, S.; Caldwell, M.; DeForest, C.; Fredvik, T.; Harra,
L.; Janvier, M.; Kucera, T. A.; Giunta, A. S.; Grundy, T.; Müller,
D.; Parenti, S.; Schmutz, W. K.; Schühle, U.; Sidher, S.; Teriaca,
L.; Thompson, W. T.; Williams, D.
2020AGUFMSH038..09Z Altcode:
Linking solar activity on the surface and in the corona to the inner
heliosphere is one of Solar Orbiter's main goals. Its UV spectrometer
SPICE (SPectral Imaging of the Coronal Environment) will provide
relative abundance measurements which will be key in this quest
as different structures on the Sun have different abundances as a
consequence of the FIP (First Ionization Potential) effect. Solar
Orbiter's unique combination of remote sensing and in-situ instruments
coupled with observation from other missions such as Parker Solar
Probe will allow us to compare in-situ and remote sensing composition
data. With the addition of modeling, these new results will allow us
to trace back the source of heliospheric plasma. As high telemetry
will not always be available with SPICE, we have developed a method
for measuring relative abundances that is both telemetry efficient
and reliable. Unlike methods based on Differential Emission Measure
(DEM) inversion, the Linear Combination Ratio (LCR) method does not
require a large number of spectral lines. This new method is based
on linear combinations of UV spectral lines. The coefficients of
the combinations are optimized such that the ratio of two linear
combinations of radiances would yield the relative abundance of two
elements. We present some abundance diagnostics tested on different
combinations of spectral lines observable by SPICE.
---------------------------------------------------------
Title: Dynamics and thermal structure in the quiet Sun seen by SPICE
Authors: Peter, H.; Aznar Cuadrado, R.; Schühle, U.; Teriaca, L.;
Auchere, F.; Carlsson, M.; Fludra, A.; Hassler, D.; Buchlin, E.;
Caminade, S.; Caldwell, M.; DeForest, C.; Fredvik, T.; Harra, L. K.;
Janvier, M.; Kucera, T. A.; Giunta, A. S.; Grundy, T.; Müller, D.;
Parenti, S.; Schmutz, W. K.; Sidher, S.; Thompson, W. T.; Williams,
D.; Young, P. R.
2020AGUFMSH038..03P Altcode:
We will present some of the early data of the Spectral Imaging of the
Coronal Environment (SPICE) instrument on Solar Orbiter. One of the
unique features of SPICE is its capability to record a wide range of
wavelengths in the extreme UV with the possibility to record spectral
lines giving access to a continuous plasma temperature range from 10.000
K to well above 1 MK. The data taken so far were for commissioning
purposes and they can be used for a preliminary evaluation of the
science performance of the instrument. Here we will concentrate on
sample spectra covering the whole wavelength region and on the early
raster maps acquired in bright lines in the quiet Sun close to disk
center. Looking at different quiet Sun features we investigate the
thermal structure of the atmosphere and flow structures. For this
we apply fits to the spectral profiles and check the performance in
terms of Doppler shifts and line widths to retrieve the structure of
the network in terms of dynamics. While the amount of data available
so far is limited, we will have a first look on how quiet Sun plasma
responds to heating events. For this, we will compare spectral lines
forming at different temperatures recorded at strictly the same time.
---------------------------------------------------------
Title: Observation of Smallest Ever Detected Brightening Events with
the Solar Orbiter EUI HRI-EUV Imager
Authors: Parenti, S.; Berghmans, D.; Buchlin, E.; Teriaca, L.; Auchere,
F.; Harra, L.; Long, D.; Rochus, P. L.; Schühle, U.; Aznar Cuadrado,
R.; Gissot, S.; Kraaikamp, E.; Smith, P.; Stegen, K.; Verbeeck, C.
2020AGUFMSH038..01P Altcode:
The Extreme Ultraviolet Imager (EUI) suite on board Solar Orbiter
acquired its first images in May 2020. The passband of the 17.4 nm
High Resolution Imager (HRI-EUV) is dominated by emission lines of
Fe IX and Fe X, that is the 1 million degree solar corona. The solar
atmosphere at this temperature is dynamic at all scales, down to the
highest spatial resolution available from instruments priori to Solar
Orbiter. During the Commissioning phase, HRI-EUV acquired several high
temporal resolution (a few seconds) sequences at quiet Sun regions at
disk center. The instrument revealed a multitude of brightenings at
the smallest-ever detectable spatial scales which, at that time, was
about 400 km (two pixels). These events appear to be present everywhere
all the time. We present the first results of the analysis of these
sequences with the aim of understanding the role of these small scale
events in the heating of the solar corona.
---------------------------------------------------------
Title: First Results From SPICE EUV Spectrometer on Solar Orbiter
Authors: Fludra, A.; Caldwell, M.; Giunta, A. S.; Grundy, T.; Guest,
S.; Sidher, S.; Auchere, F.; Carlsson, M.; Hassler, D.; Peter, H.;
Aznar Cuadrado, R.; Buchlin, E.; Caminade, S.; DeForest, C.; Fredvik,
T.; Harra, L. K.; Janvier, M.; Kucera, T. A.; Leeks, S.; Mueller,
D.; Parenti, S.; Schmutz, W. K.; Schühle, U.; Teriaca, L.; Thompson,
W. T.; Tustain, S.; Williams, D.; Young, P. R.
2020AGUFMSH038..02F Altcode:
SPICE (Spectral Imaging of Coronal Environment) is one of the remote
sensing instruments onboard Solar Orbiter. It is an EUV imaging
spectrometer observing the Sun in two wavelength bands: 69.6-79.4 nm
and 96.6-105.1 nm. SPICE is capable of recording full spectra in these
bands with exposures as short as 1s. SPICE is the only Solar Orbiter
instrument that can measure EUV spectra from the disk and low corona
of the Sun and record all spectral lines simultaneously. SPICE uses
one of three narrow slits, 2"x11', 4”x11', 6”x11', or a wide slit
30”x14'. The primary mirror can be scanned in a direction perpendicular
to the slit, allowing raster images of up to 16' in size. <P />We
present an overview of the first SPICE data taken on several days
during the instrument commissioning carried out by the RAL Space team
between 2020 April 21 and 2020 June 14. We also include results from
SPICE observations at the first Solar Orbiter perihelion at 0.52AU,
taken between June 16-21<SUP>st</SUP>. We give examples of full spectra
from the quiet Sun near disk centre and provide a list of key spectral
lines emitted in a range of temperatures between 10,000 K and over 1
million K, from neutral hydrogen and ions of carbon, oxygen, nitrogen,
neon, sulphur and magnesium. We show examples of first raster images
in several strong lines, obtained with different slits and a range
of exposure times between 5s and 180s. We describe the temperature
coverage and density diagnostics, determination of plasma flows, and
discuss possible applications to studies of the elemental abundances
in the corona. We also show the first off-limb measurements with SPICE,
as obtained when the spacecraft pointed at the limb.
---------------------------------------------------------
Title: Calibrating optical distortions in the Solar Orbiter SPICE
spectrograph
Authors: Thompson, W. T.; Schühle, U.; Young, P. R.; Auchere, F.;
Carlsson, M.; Fludra, A.; Hassler, D.; Peter, H.; Aznar Cuadrado, R.;
Buchlin, E.; Caldwell, M.; DeForest, C.; Fredvik, T.; Harra, L. K.;
Janvier, M.; Kucera, T. A.; Giunta, A. S.; Grundy, T.; Müller, D.;
Parenti, S.; Caminade, S.; Schmutz, W. K.; Teriaca, L.; Williams,
D.; Sidher, S.
2020AGUFMSH0360029T Altcode:
The Spectral Imaging of the Coronal Environment (SPICE) instrument on
Solar Orbiter is a high-resolution imaging spectrometer operating
at extreme ultraviolet (EUV) wavelengths from 70.4-79.0 nm and
97.3-104.9 nm. A single-mirror off-axis paraboloid focuses the solar
image onto the entrance slit of the spectrometer section. A Toroidal
Variable Line Space (TVLS) grating images the entrance slit onto a
pair of MCP-intensified APS detectors. Ray-tracing analysis prior
to launch showed that the instrument was subject to a number of
small image distortions which need to be corrected in the final data
product. We compare the ray tracing results with measurements made in
flight. Co-alignment with other telescopes on Solar Orbiter will also
be examined.
---------------------------------------------------------
Title: First results from the EUI and SPICE observations of Alpha
Leo near Solar Orbiter first perihelion
Authors: Buchlin, E.; Teriaca, L.; Giunta, A. S.; Grundy, T.; Andretta,
V.; Auchere, F.; Peter, H.; Berghmans, D.; Carlsson, M.; Fludra, A.;
Harra, L.; Hassler, D.; Long, D.; Rochus, P. L.; Schühle, U.; Aznar
Cuadrado, R.; Caldwell, M.; Caminade, S.; DeForest, C.; Fredvik, T.;
Gissot, S.; Heerlein, K.; Janvier, M.; Kraaikamp, E.; Kucera, T. A.;
Müller, D.; Parenti, S.; Schmutz, W. K.; Sidher, S.; Smith, P.;
Stegen, K.; Thompson, W. T.; Verbeeck, C.; Williams, D.; Young, P. R.
2020AGUFMSH0360024B Altcode:
On June 16th 2020 Solar Orbiter made a dedicated observing campaign
where the spacecraft pointed to the solar limb to allow some of the
high resolution instruments to observe the ingress (at the east limb)
and later the egress (west limb) of the occultation of the star Alpha
Leonis by the solar disk. The star was chosen because its luminosity and
early spectral type ensure high and stable flux at wavelengths between
100 and 122 nanometers, a range observed by the High Resolution EUI
Lyman alpha telescope (HRI-LYA) and by the long wavelength channel
of the SPICE spectrograph. Star observations, when feasible, allow
to gather a great deal of information on the instrument performances,
such as the radiometric performance and the instrument optical point
spread function (PSF). <P />We report here the first results from the
above campaign for the two instruments.
---------------------------------------------------------
Title: First results from combined EUI and SPICE observations of
Lyman lines of Hydrogen and He II
Authors: Teriaca, L.; Aznar Cuadrado, R.; Giunta, A. S.; Grundy, T.;
Parenti, S.; Auchere, F.; Vial, J. C.; Fludra, A.; Berghmans, D.;
Carlsson, M.; Harra, L.; Hassler, D.; Long, D.; Peter, H.; Rochus,
P. L.; Schühle, U.; Buchlin, E.; Caldwell, M.; Caminade, S.; DeForest,
C.; Fredvik, T.; Gissot, S.; Heerlein, K.; Janvier, M.; Kraaikamp,
E.; Kucera, T. A.; Mueller, D.; Schmutz, W. K.; Sidher, S.; Smith, P.;
Stegen, K.; Thompson, W. T.; Verbeeck, C.; Williams, D.; Young, P. R.
2020AGUFMSH0360003T Altcode:
The Solar Orbiter spacecraft carries a powerful set of remote
sensing instruments that allow studying the solar atmosphere with
unprecedented diagnostic capabilities. Many such diagnostics require
the simultaneous usage of more than one instrument. One example of that
is the capability, for the first time, to obtain (near) simultaneous
spatially resolved observations of the emission from the first three
lines of the Lyman series of hydrogen and of He II Lyman alpha. In fact,
the SPectral Imaging of the Coronal Environment (SPICE) spectrometer
can observe the Lyman beta and gamma lines in its long wavelength
(SPICE-LW) channel, the High Resolution Lyman Alpha (HRI-LYA) telescope
of the Extreme Ultraviolet Imager (EUI) acquires narrow band images in
the Lyman alpha line while the Full Disk Imager (FSI) of EUI can take
images dominated by the Lyman alpha line of ionized Helium at 30.4 nm
(FSI-304). Being hydrogen and helium the main components of our star,
these very bright transitions play an important role in the energy
budget of the outer atmosphere via radiative losses and the measurement
of their profiles and radiance ratios is a fundamental constraint to
any comprehensive modelization effort of the upper solar chromosphere
and transition region. Additionally, monitoring their average ratios
can serve as a check out for the relative radiometric performance of
the two instruments throughout the mission. Although the engineering
data acquired so far are far from ideal in terms of time simultaneity
(often only within about 1 h) and line coverage (often only Lyman beta
was acquired by SPICE and not always near simultaneous images from all
three telescopes are available) the analysis we present here still
offers a great opportunity to have a first look at the potential of
this diagnostic from the two instruments. In fact, we have identified
a series of datasets obtained at disk center and at various positions
at the solar limb that allow studying the Lyman alpha to beta radiance
ratio and their relation to He II 30.4 as a function of the position
on the Sun (disk center versus limb and quiet Sun versus coronal holes).
---------------------------------------------------------
Title: A joint study of Solar Orbiter first data and PSP E5 through
3D MHD modeling
Authors: Réville, V.; Strugarek, A.; Brun, S.; Rouillard, A. P.;
Velli, M. C. M.; Poirier, N.; Parenti, S.; Hazra, S.; Perri, B.;
Pinto, R.; Lavraud, B.; Louarn, P.; Fedorov, A.; Owen, C. J.; Bruno,
R.; Livi, R.; Horbury, T. S.; O'Brien, H.; Evans, V.; Angelini, V.;
Bale, S. D.; Kasper, J. C.
2020AGUFMSH039..09R Altcode:
The first remote sensing window of Solar Orbiter started mid-June
2020. After a successful commissioning, Solar Orbiter in situ
instruments were then continuously monitoring. This window
is coincidentally close to the fifth perihelion of Parker Solar
Probe. This offers an opportunity for a joint study between the two
probes' data. We use a 3D MHD model of a turbulence driven solar wind,
and compare the structure of the inner heliosphere obtained by the model
and the available in situ and remote sensing data of the spacecraft. We
discuss the key features of the model and tricky points that require
care, such as the choice of the input magnetogram. In particular,
we notice the strong influence of two active regions on the magnetic
sectors and solar wind properties. These regions will be increasingly
important features in future encounters and joint studies as we go
towards solar maximum.
---------------------------------------------------------
Title: Coordination within the remote sensing payload on the Solar
Orbiter mission
Authors: Auchère, F.; Andretta, V.; Antonucci, E.; Bach, N.;
Battaglia, M.; Bemporad, A.; Berghmans, D.; Buchlin, E.; Caminade,
S.; Carlsson, M.; Carlyle, J.; Cerullo, J. J.; Chamberlin, P. C.;
Colaninno, R. C.; Davila, J. M.; De Groof, A.; Etesi, L.; Fahmy,
S.; Fineschi, S.; Fludra, A.; Gilbert, H. R.; Giunta, A.; Grundy,
T.; Haberreiter, M.; Harra, L. K.; Hassler, D. M.; Hirzberger, J.;
Howard, R. A.; Hurford, G.; Kleint, L.; Kolleck, M.; Krucker, S.;
Lagg, A.; Landini, F.; Long, D. M.; Lefort, J.; Lodiot, S.; Mampaey,
B.; Maloney, S.; Marliani, F.; Martinez-Pillet, V.; McMullin, D. R.;
Müller, D.; Nicolini, G.; Orozco Suarez, D.; Pacros, A.; Pancrazzi,
M.; Parenti, S.; Peter, H.; Philippon, A.; Plunkett, S.; Rich, N.;
Rochus, P.; Rouillard, A.; Romoli, M.; Sanchez, L.; Schühle, U.;
Sidher, S.; Solanki, S. K.; Spadaro, D.; St Cyr, O. C.; Straus, T.;
Tanco, I.; Teriaca, L.; Thompson, W. T.; del Toro Iniesta, J. C.;
Verbeeck, C.; Vourlidas, A.; Watson, C.; Wiegelmann, T.; Williams,
D.; Woch, J.; Zhukov, A. N.; Zouganelis, I.
2020A&A...642A...6A Altcode:
Context. To meet the scientific objectives of the mission, the Solar
Orbiter spacecraft carries a suite of in-situ (IS) and remote sensing
(RS) instruments designed for joint operations with inter-instrument
communication capabilities. Indeed, previous missions have shown that
the Sun (imaged by the RS instruments) and the heliosphere (mainly
sampled by the IS instruments) should be considered as an integrated
system rather than separate entities. Many of the advances expected
from Solar Orbiter rely on this synergistic approach between IS and
RS measurements. <BR /> Aims: Many aspects of hardware development,
integration, testing, and operations are common to two or more
RS instruments. In this paper, we describe the coordination effort
initiated from the early mission phases by the Remote Sensing Working
Group. We review the scientific goals and challenges, and give an
overview of the technical solutions devised to successfully operate
these instruments together. <BR /> Methods: A major constraint for the
RS instruments is the limited telemetry (TM) bandwidth of the Solar
Orbiter deep-space mission compared to missions in Earth orbit. Hence,
many of the strategies developed to maximise the scientific return from
these instruments revolve around the optimisation of TM usage, relying
for example on onboard autonomy for data processing, compression,
and selection for downlink. The planning process itself has been
optimised to alleviate the dynamic nature of the targets, and an
inter-instrument communication scheme has been implemented which can
be used to autonomously alter the observing modes. We also outline the
plans for in-flight cross-calibration, which will be essential to the
joint data reduction and analysis. <BR /> Results: The RS instrument
package on Solar Orbiter will carry out comprehensive measurements
from the solar interior to the inner heliosphere. Thanks to the close
coordination between the instrument teams and the European Space
Agency, several challenges specific to the RS suite were identified
and addressed in a timely manner.
---------------------------------------------------------
Title: Models and data analysis tools for the Solar Orbiter mission
Authors: Rouillard, A. P.; Pinto, R. F.; Vourlidas, A.; De Groof, A.;
Thompson, W. T.; Bemporad, A.; Dolei, S.; Indurain, M.; Buchlin, E.;
Sasso, C.; Spadaro, D.; Dalmasse, K.; Hirzberger, J.; Zouganelis, I.;
Strugarek, A.; Brun, A. S.; Alexandre, M.; Berghmans, D.; Raouafi,
N. E.; Wiegelmann, T.; Pagano, P.; Arge, C. N.; Nieves-Chinchilla,
T.; Lavarra, M.; Poirier, N.; Amari, T.; Aran, A.; Andretta, V.;
Antonucci, E.; Anastasiadis, A.; Auchère, F.; Bellot Rubio, L.;
Nicula, B.; Bonnin, X.; Bouchemit, M.; Budnik, E.; Caminade, S.;
Cecconi, B.; Carlyle, J.; Cernuda, I.; Davila, J. M.; Etesi, L.;
Espinosa Lara, F.; Fedorov, A.; Fineschi, S.; Fludra, A.; Génot,
V.; Georgoulis, M. K.; Gilbert, H. R.; Giunta, A.; Gomez-Herrero, R.;
Guest, S.; Haberreiter, M.; Hassler, D.; Henney, C. J.; Howard, R. A.;
Horbury, T. S.; Janvier, M.; Jones, S. I.; Kozarev, K.; Kraaikamp,
E.; Kouloumvakos, A.; Krucker, S.; Lagg, A.; Linker, J.; Lavraud,
B.; Louarn, P.; Maksimovic, M.; Maloney, S.; Mann, G.; Masson, A.;
Müller, D.; Önel, H.; Osuna, P.; Orozco Suarez, D.; Owen, C. J.;
Papaioannou, A.; Pérez-Suárez, D.; Rodriguez-Pacheco, J.; Parenti,
S.; Pariat, E.; Peter, H.; Plunkett, S.; Pomoell, J.; Raines, J. M.;
Riethmüller, T. L.; Rich, N.; Rodriguez, L.; Romoli, M.; Sanchez,
L.; Solanki, S. K.; St Cyr, O. C.; Straus, T.; Susino, R.; Teriaca,
L.; del Toro Iniesta, J. C.; Ventura, R.; Verbeeck, C.; Vilmer, N.;
Warmuth, A.; Walsh, A. P.; Watson, C.; Williams, D.; Wu, Y.; Zhukov,
A. N.
2020A&A...642A...2R Altcode:
Context. The Solar Orbiter spacecraft will be equipped with a wide
range of remote-sensing (RS) and in situ (IS) instruments to record
novel and unprecedented measurements of the solar atmosphere and
the inner heliosphere. To take full advantage of these new datasets,
tools and techniques must be developed to ease multi-instrument and
multi-spacecraft studies. In particular the currently inaccessible
low solar corona below two solar radii can only be observed
remotely. Furthermore techniques must be used to retrieve coronal
plasma properties in time and in three dimensional (3D) space. Solar
Orbiter will run complex observation campaigns that provide interesting
opportunities to maximise the likelihood of linking IS data to their
source region near the Sun. Several RS instruments can be directed
to specific targets situated on the solar disk just days before
data acquisition. To compare IS and RS, data we must improve our
understanding of how heliospheric probes magnetically connect to the
solar disk. <BR /> Aims: The aim of the present paper is to briefly
review how the current modelling of the Sun and its atmosphere
can support Solar Orbiter science. We describe the results of a
community-led effort by European Space Agency's Modelling and Data
Analysis Working Group (MADAWG) to develop different models, tools,
and techniques deemed necessary to test different theories for the
physical processes that may occur in the solar plasma. The focus here
is on the large scales and little is described with regards to kinetic
processes. To exploit future IS and RS data fully, many techniques have
been adapted to model the evolving 3D solar magneto-plasma from the
solar interior to the solar wind. A particular focus in the paper is
placed on techniques that can estimate how Solar Orbiter will connect
magnetically through the complex coronal magnetic fields to various
photospheric and coronal features in support of spacecraft operations
and future scientific studies. <BR /> Methods: Recent missions such as
STEREO, provided great opportunities for RS, IS, and multi-spacecraft
studies. We summarise the achievements and highlight the challenges
faced during these investigations, many of which motivated the Solar
Orbiter mission. We present the new tools and techniques developed
by the MADAWG to support the science operations and the analysis of
the data from the many instruments on Solar Orbiter. <BR /> Results:
This article reviews current modelling and tool developments that ease
the comparison of model results with RS and IS data made available
by current and upcoming missions. It also describes the modelling
strategy to support the science operations and subsequent exploitation
of Solar Orbiter data in order to maximise the scientific output
of the mission. <BR /> Conclusions: The on-going community effort
presented in this paper has provided new models and tools necessary
to support mission operations as well as the science exploitation of
the Solar Orbiter data. The tools and techniques will no doubt evolve
significantly as we refine our procedure and methodology during the
first year of operations of this highly promising mission.
---------------------------------------------------------
Title: The Solar Orbiter Science Activity Plan. Translating solar
and heliospheric physics questions into action
Authors: Zouganelis, I.; De Groof, A.; Walsh, A. P.; Williams, D. R.;
Müller, D.; St Cyr, O. C.; Auchère, F.; Berghmans, D.; Fludra,
A.; Horbury, T. S.; Howard, R. A.; Krucker, S.; Maksimovic, M.;
Owen, C. J.; Rodríguez-Pacheco, J.; Romoli, M.; Solanki, S. K.;
Watson, C.; Sanchez, L.; Lefort, J.; Osuna, P.; Gilbert, H. R.;
Nieves-Chinchilla, T.; Abbo, L.; Alexandrova, O.; Anastasiadis, A.;
Andretta, V.; Antonucci, E.; Appourchaux, T.; Aran, A.; Arge, C. N.;
Aulanier, G.; Baker, D.; Bale, S. D.; Battaglia, M.; Bellot Rubio,
L.; Bemporad, A.; Berthomier, M.; Bocchialini, K.; Bonnin, X.; Brun,
A. S.; Bruno, R.; Buchlin, E.; Büchner, J.; Bucik, R.; Carcaboso,
F.; Carr, R.; Carrasco-Blázquez, I.; Cecconi, B.; Cernuda Cangas, I.;
Chen, C. H. K.; Chitta, L. P.; Chust, T.; Dalmasse, K.; D'Amicis, R.;
Da Deppo, V.; De Marco, R.; Dolei, S.; Dolla, L.; Dudok de Wit, T.;
van Driel-Gesztelyi, L.; Eastwood, J. P.; Espinosa Lara, F.; Etesi,
L.; Fedorov, A.; Félix-Redondo, F.; Fineschi, S.; Fleck, B.; Fontaine,
D.; Fox, N. J.; Gandorfer, A.; Génot, V.; Georgoulis, M. K.; Gissot,
S.; Giunta, A.; Gizon, L.; Gómez-Herrero, R.; Gontikakis, C.; Graham,
G.; Green, L.; Grundy, T.; Haberreiter, M.; Harra, L. K.; Hassler,
D. M.; Hirzberger, J.; Ho, G. C.; Hurford, G.; Innes, D.; Issautier,
K.; James, A. W.; Janitzek, N.; Janvier, M.; Jeffrey, N.; Jenkins,
J.; Khotyaintsev, Y.; Klein, K. -L.; Kontar, E. P.; Kontogiannis,
I.; Krafft, C.; Krasnoselskikh, V.; Kretzschmar, M.; Labrosse, N.;
Lagg, A.; Landini, F.; Lavraud, B.; Leon, I.; Lepri, S. T.; Lewis,
G. R.; Liewer, P.; Linker, J.; Livi, S.; Long, D. M.; Louarn, P.;
Malandraki, O.; Maloney, S.; Martinez-Pillet, V.; Martinovic, M.;
Masson, A.; Matthews, S.; Matteini, L.; Meyer-Vernet, N.; Moraitis,
K.; Morton, R. J.; Musset, S.; Nicolaou, G.; Nindos, A.; O'Brien,
H.; Orozco Suarez, D.; Owens, M.; Pancrazzi, M.; Papaioannou, A.;
Parenti, S.; Pariat, E.; Patsourakos, S.; Perrone, D.; Peter, H.;
Pinto, R. F.; Plainaki, C.; Plettemeier, D.; Plunkett, S. P.; Raines,
J. M.; Raouafi, N.; Reid, H.; Retino, A.; Rezeau, L.; Rochus, P.;
Rodriguez, L.; Rodriguez-Garcia, L.; Roth, M.; Rouillard, A. P.;
Sahraoui, F.; Sasso, C.; Schou, J.; Schühle, U.; Sorriso-Valvo, L.;
Soucek, J.; Spadaro, D.; Stangalini, M.; Stansby, D.; Steller, M.;
Strugarek, A.; Štverák, Š.; Susino, R.; Telloni, D.; Terasa, C.;
Teriaca, L.; Toledo-Redondo, S.; del Toro Iniesta, J. C.; Tsiropoula,
G.; Tsounis, A.; Tziotziou, K.; Valentini, F.; Vaivads, A.; Vecchio,
A.; Velli, M.; Verbeeck, C.; Verdini, A.; Verscharen, D.; Vilmer, N.;
Vourlidas, A.; Wicks, R.; Wimmer-Schweingruber, R. F.; Wiegelmann,
T.; Young, P. R.; Zhukov, A. N.
2020A&A...642A...3Z Altcode: 2020arXiv200910772Z
Solar Orbiter is the first space mission observing the solar plasma
both in situ and remotely, from a close distance, in and out of the
ecliptic. The ultimate goal is to understand how the Sun produces
and controls the heliosphere, filling the Solar System and driving
the planetary environments. With six remote-sensing and four in-situ
instrument suites, the coordination and planning of the operations are
essential to address the following four top-level science questions:
(1) What drives the solar wind and where does the coronal magnetic field
originate?; (2) How do solar transients drive heliospheric variability?;
(3) How do solar eruptions produce energetic particle radiation that
fills the heliosphere?; (4) How does the solar dynamo work and drive
connections between the Sun and the heliosphere? Maximising the
mission's science return requires considering the characteristics
of each orbit, including the relative position of the spacecraft
to Earth (affecting downlink rates), trajectory events (such
as gravitational assist manoeuvres), and the phase of the solar
activity cycle. Furthermore, since each orbit's science telemetry
will be downloaded over the course of the following orbit, science
operations must be planned at mission level, rather than at the level
of individual orbits. It is important to explore the way in which those
science questions are translated into an actual plan of observations
that fits into the mission, thus ensuring that no opportunities are
missed. First, the overarching goals are broken down into specific,
answerable questions along with the required observations and the
so-called Science Activity Plan (SAP) is developed to achieve this. The
SAP groups objectives that require similar observations into Solar
Orbiter Observing Plans, resulting in a strategic, top-level view of
the optimal opportunities for science observations during the mission
lifetime. This allows for all four mission goals to be addressed. In
this paper, we introduce Solar Orbiter's SAP through a series of
examples and the strategy being followed.
---------------------------------------------------------
Title: The Solar Orbiter SPICE instrument. An extreme UV imaging
spectrometer
Authors: SPICE Consortium; Anderson, M.; Appourchaux, T.; Auchère, F.;
Aznar Cuadrado, R.; Barbay, J.; Baudin, F.; Beardsley, S.; Bocchialini,
K.; Borgo, B.; Bruzzi, D.; Buchlin, E.; Burton, G.; Büchel, V.;
Caldwell, M.; Caminade, S.; Carlsson, M.; Curdt, W.; Davenne, J.;
Davila, J.; Deforest, C. E.; Del Zanna, G.; Drummond, D.; Dubau,
J.; Dumesnil, C.; Dunn, G.; Eccleston, P.; Fludra, A.; Fredvik, T.;
Gabriel, A.; Giunta, A.; Gottwald, A.; Griffin, D.; Grundy, T.; Guest,
S.; Gyo, M.; Haberreiter, M.; Hansteen, V.; Harrison, R.; Hassler,
D. M.; Haugan, S. V. H.; Howe, C.; Janvier, M.; Klein, R.; Koller,
S.; Kucera, T. A.; Kouliche, D.; Marsch, E.; Marshall, A.; Marshall,
G.; Matthews, S. A.; McQuirk, C.; Meining, S.; Mercier, C.; Morris,
N.; Morse, T.; Munro, G.; Parenti, S.; Pastor-Santos, C.; Peter, H.;
Pfiffner, D.; Phelan, P.; Philippon, A.; Richards, A.; Rogers, K.;
Sawyer, C.; Schlatter, P.; Schmutz, W.; Schühle, U.; Shaughnessy,
B.; Sidher, S.; Solanki, S. K.; Speight, R.; Spescha, M.; Szwec, N.;
Tamiatto, C.; Teriaca, L.; Thompson, W.; Tosh, I.; Tustain, S.; Vial,
J. -C.; Walls, B.; Waltham, N.; Wimmer-Schweingruber, R.; Woodward,
S.; Young, P.; de Groof, A.; Pacros, A.; Williams, D.; Müller, D.
2020A&A...642A..14S Altcode: 2019arXiv190901183A; 2019arXiv190901183S
<BR /> Aims: The Spectral Imaging of the Coronal Environment (SPICE)
instrument is a high-resolution imaging spectrometer operating at
extreme ultraviolet wavelengths. In this paper, we present the concept,
design, and pre-launch performance of this facility instrument on the
ESA/NASA Solar Orbiter mission. <BR /> Methods: The goal of this paper
is to give prospective users a better understanding of the possible
types of observations, the data acquisition, and the sources that
contribute to the instrument's signal. <BR /> Results: The paper
discusses the science objectives, with a focus on the SPICE-specific
aspects, before presenting the instrument's design, including optical,
mechanical, thermal, and electronics aspects. This is followed by a
characterisation and calibration of the instrument's performance. The
paper concludes with descriptions of the operations concept and data
processing. <BR /> Conclusions: The performance measurements of the
various instrument parameters meet the requirements derived from the
mission's science objectives. The SPICE instrument is ready to perform
measurements that will provide vital contributions to the scientific
success of the Solar Orbiter mission.
---------------------------------------------------------
Title: The Solar Orbiter EUI instrument: The Extreme Ultraviolet
Imager
Authors: Rochus, P.; Auchère, F.; Berghmans, D.; Harra, L.; Schmutz,
W.; Schühle, U.; Addison, P.; Appourchaux, T.; Aznar Cuadrado,
R.; Baker, D.; Barbay, J.; Bates, D.; BenMoussa, A.; Bergmann, M.;
Beurthe, C.; Borgo, B.; Bonte, K.; Bouzit, M.; Bradley, L.; Büchel,
V.; Buchlin, E.; Büchner, J.; Cabé, F.; Cadiergues, L.; Chaigneau,
M.; Chares, B.; Choque Cortez, C.; Coker, P.; Condamin, M.; Coumar,
S.; Curdt, W.; Cutler, J.; Davies, D.; Davison, G.; Defise, J. -M.;
Del Zanna, G.; Delmotte, F.; Delouille, V.; Dolla, L.; Dumesnil, C.;
Dürig, F.; Enge, R.; François, S.; Fourmond, J. -J.; Gillis, J. -M.;
Giordanengo, B.; Gissot, S.; Green, L. M.; Guerreiro, N.; Guilbaud,
A.; Gyo, M.; Haberreiter, M.; Hafiz, A.; Hailey, M.; Halain, J. -P.;
Hansotte, J.; Hecquet, C.; Heerlein, K.; Hellin, M. -L.; Hemsley, S.;
Hermans, A.; Hervier, V.; Hochedez, J. -F.; Houbrechts, Y.; Ihsan,
K.; Jacques, L.; Jérôme, A.; Jones, J.; Kahle, M.; Kennedy, T.;
Klaproth, M.; Kolleck, M.; Koller, S.; Kotsialos, E.; Kraaikamp, E.;
Langer, P.; Lawrenson, A.; Le Clech', J. -C.; Lenaerts, C.; Liebecq,
S.; Linder, D.; Long, D. M.; Mampaey, B.; Markiewicz-Innes, D.;
Marquet, B.; Marsch, E.; Matthews, S.; Mazy, E.; Mazzoli, A.; Meining,
S.; Meltchakov, E.; Mercier, R.; Meyer, S.; Monecke, M.; Monfort,
F.; Morinaud, G.; Moron, F.; Mountney, L.; Müller, R.; Nicula, B.;
Parenti, S.; Peter, H.; Pfiffner, D.; Philippon, A.; Phillips, I.;
Plesseria, J. -Y.; Pylyser, E.; Rabecki, F.; Ravet-Krill, M. -F.;
Rebellato, J.; Renotte, E.; Rodriguez, L.; Roose, S.; Rosin, J.;
Rossi, L.; Roth, P.; Rouesnel, F.; Roulliay, M.; Rousseau, A.; Ruane,
K.; Scanlan, J.; Schlatter, P.; Seaton, D. B.; Silliman, K.; Smit,
S.; Smith, P. J.; Solanki, S. K.; Spescha, M.; Spencer, A.; Stegen,
K.; Stockman, Y.; Szwec, N.; Tamiatto, C.; Tandy, J.; Teriaca, L.;
Theobald, C.; Tychon, I.; van Driel-Gesztelyi, L.; Verbeeck, C.;
Vial, J. -C.; Werner, S.; West, M. J.; Westwood, D.; Wiegelmann, T.;
Willis, G.; Winter, B.; Zerr, A.; Zhang, X.; Zhukov, A. N.
2020A&A...642A...8R Altcode:
Context. The Extreme Ultraviolet Imager (EUI) is part of the remote
sensing instrument package of the ESA/NASA Solar Orbiter mission
that will explore the inner heliosphere and observe the Sun from
vantage points close to the Sun and out of the ecliptic. Solar Orbiter
will advance the "connection science" between solar activity and the
heliosphere. <BR /> Aims: With EUI we aim to improve our understanding
of the structure and dynamics of the solar atmosphere, globally as well
as at high resolution, and from high solar latitude perspectives. <BR />
Methods: The EUI consists of three telescopes, the Full Sun Imager and
two High Resolution Imagers, which are optimised to image in Lyman-α
and EUV (17.4 nm, 30.4 nm) to provide a coverage from chromosphere
up to corona. The EUI is designed to cope with the strong constraints
imposed by the Solar Orbiter mission characteristics. Limited telemetry
availability is compensated by state-of-the-art image compression,
onboard image processing, and event selection. The imposed power
limitations and potentially harsh radiation environment necessitate
the use of novel CMOS sensors. As the unobstructed field of view of
the telescopes needs to protrude through the spacecraft's heat shield,
the apertures have been kept as small as possible, without compromising
optical performance. This led to a systematic effort to optimise the
throughput of every optical element and the reduction of noise levels
in the sensor. <BR /> Results: In this paper we review the design
of the two elements of the EUI instrument: the Optical Bench System
and the Common Electronic Box. Particular attention is also given to
the onboard software, the intended operations, the ground software,
and the foreseen data products. <BR /> Conclusions: The EUI will
bring unique science opportunities thanks to its specific design,
its viewpoint, and to the planned synergies with the other Solar
Orbiter instruments. In particular, we highlight science opportunities
brought by the out-of-ecliptic vantage point of the solar poles,
the high-resolution imaging of the high chromosphere and corona,
and the connection to the outer corona as observed by coronagraphs.
---------------------------------------------------------
Title: Solar physics in the 2020s: DKIST, parker solar probe, and
solar orbiter as a multi-messenger constellation
Authors: Martinez Pillet, V.; Tritschler, A.; Harra, L.; Andretta, V.;
Vourlidas, A.; Raouafi, N.; Alterman, B. L.; Bellot Rubio, L.; Cauzzi,
G.; Cranmer, S. R.; Gibson, S.; Habbal, S.; Ko, Y. K.; Lepri, S. T.;
Linker, J.; Malaspina, D. M.; Matthews, S.; Parenti, S.; Petrie, G.;
Spadaro, D.; Ugarte-Urra, I.; Warren, H.; Winslow, R.
2020arXiv200408632M Altcode:
The National Science Foundation (NSF) Daniel K. Inouye Solar Telescope
(DKIST) is about to start operations at the summit of Haleakala
(Hawaii). DKIST will join the early science phases of the NASA
and ESA Parker Solar Probe and Solar Orbiter encounter missions. By
combining in-situ measurements of the near-sun plasma environment and
detail remote observations of multiple layers of the Sun, the three
observatories form an unprecedented multi-messenger constellation to
study the magnetic connectivity inside the solar system. This white
paper outlines the synergistic science that this multi-messenger
suite enables.
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Title: Spectroscopic detection of coronal plasma flows in loops
undergoing thermal non-equilibrium cycles
Authors: Pelouze, Gabriel; Auchère, Frédéric; Bocchialini, Karine;
Froment, Clara; Parenti, Susanna; Soubrié, Elie
2020A&A...634A..54P Altcode: 2019arXiv191202538P
Context. Long-period intensity pulsations were recently detected in
the EUV emission of coronal loops and attributed to cycles of plasma
evaporation and condensation driven by thermal non-equilibrium
(TNE). Numerical simulations that reproduce this phenomenon
also predict the formation of periodic flows of plasma at coronal
temperatures along some of the pulsating loops. <BR /> Aims: We aim
to detect these predicted flows of coronal-temperature plasma in
pulsating loops. <BR /> Methods: We used time series of spatially
resolved spectra from the EUV imaging spectrometer (EIS) onboard
Hinode and tracked the evolution of the Doppler velocity in loops in
which intensity pulsations have previously been detected in images
of SDO/AIA. <BR /> Results: We measured signatures of flows that are
compatible with the simulations but only for a fraction of the observed
events. We demonstrate that this low detection rate can be explained
by line of sight ambiguities combined with instrumental limitations,
such as low signal-to-noise ratio or insufficient cadence. <P
/>Movies associated to Figs. 1, 4, 7, 10 are available at <A
href="https://www.aanda.org/10.1051/0004-6361/201935872/olm">https://www.aanda.org</A>
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Title: The SPICE (Spectral Imaging of the Coronal Environment)
Ultraviolet Imaging Spectrograph Investigation
Authors: Hassler, D.; Auchere, F.; Carlsson, M.; Fludra, A.; Giunta,
A. S.; Mueller, D.; Peter, H.; Parenti, S.; Teriaca, L.; Fredvik, T.
2019AGUFMSH24A..02H Altcode:
One of the primary objectives of the Solar Orbiter mission is to link
remote sensing observations of the solar surface structures with in-situ
observations of solar wind streams. The SPICE (Spectral Imaging of the
Coronal Environment) instrument will characterize the plasma properties
of regions near the Sun to directly compare with in-situ measurements
from both Solar Orbiter & Parker Solar Probe. Specifically, SPICE
will map outflow velocities of surface features to solar wind structures
with similar composition (FIP, M/q) measured in-situ by the SWA/HIS
instrument on Solar Orbiter. These observations will help discriminate
models of solar wind origin by matching composition signatures in
solar wind streams to surface feature composition, and discriminate
physical processes that inject material from closed structures into
solar wind streams. <P />This presentation will provide an overview of
the SPICE investigation, including science & measurement objective,
instrument design, capabilities and performance as measured during
calibration prior to delivery to the Solar Orbiter spacecraft. The
presentation will also provide a description of the operations concept
and data processing during the mission.
---------------------------------------------------------
Title: Linking the Sun to the heliosphere using composition data
and modelling: coronal jets as a test case
Authors: Wimmer-Schweingruber, Robert F.; Parenti, Susanna; Del Zanna,
G.; Edmondson, J.; Giunta, A.; Hansteen, V. H.; Higginson, A.; Lepri,
S.; Laming, M.; Lynch, B. J.; von Steiger, R. E.; Wiegelmann, T.;
Zambrana Prado, N.
2019shin.confE.231W Altcode:
Understanding the formation and evolution of the solar wind is still
a priority in the Solar and Heliospheric communities. We expect
a significant progress in terms of observations with the upcoming
Solar Orbiter mission (launch in 2020), which will provide detailed
in-situ measurements of the solar wind and several remote-sensing
observations. However, real progress will only be possible if we
improve our understanding of the physical link between what measured
in-situ and its source regions on the Sun. In this respect, the plasma
chemical and charge-state compositions are considered good diagnostic
tools. In this paper we present results obtained from an extensive team
work aiming at providing solid diagnostics for linking the in-situ and
the remote sensing measurements. For our test cases, we selected two
periods when a single active region produced, close to its sunspot,
jets which had a counterpart signature in the Heliosphere in the form
of type-III radio bursts. These jets therefore marked magnetically
open regions expanding in the heliosphere. Firstly, we looked for
signatures of the open field associated with the active regions in
in-situ data from ACE and WIND, finding potential tracers. Secondly,
we studied the magnetic topology of the full Sun and Heliosphere with
extrapolations of photospheric data and MHD modeling. We found that
the open field area is consistent with the source and evolution of the
jets, as observed with EUV imagers (SDO/AIA, STEREO/EUVI). Thirdly, we
analysed remote sensing EUV spectroscopic observations to measure the
plasma conditions (densities, temperatures and chemical composition)
whenever available. We then modeled the solar wind and charge
state evolution with the solar distance along the open fields to
establish a link between the in-situ signatures and the remote sensing
observations. We discuss the various difficulties associated with such
studies, and highlight how Solar Orbiter measurements can improve them.
---------------------------------------------------------
Title: Modeling the Solar-Heliospheric Connection of Active
Region-Adjacent Open Fields
Authors: Lynch, Benjamin J.; Higginson, A. K.; Edmondson, J. K.;
Parenti, S.
2019shin.confE.234L Altcode:
We present MHD simulation results of the 2010 August 02 coronal jet
rooted in the negative polarity spot of AR 11092. We examine the
'steady state' MHD solar wind outflow and compare the helmet streamer
and coronal hole configurations to the PFSS extrapolations obtained
using NSO GONG and SDO HMI synoptic maps. We compare the structure of
the open fields in the periphery of the AR to EUV imaging in the low
corona. We model the macroscopic twist propagation of the jet as a
simple rotational flow imposed at the lower boundary and examine its
interaction with and the evolution of the open-closed flux system
boundary. We show how the disturbance maps to the ecliptic plane
and compare the simulation dynamics to STEREO EUV and white light
observations.
---------------------------------------------------------
Title: Elemental composition in quiescent prominences
Authors: Parenti, S.; Del Zanna, G.; Vial, J. -C.
2019A&A...625A..52P Altcode: 2019arXiv190500871P
Context. The first ionization potential (FIP) bias is currently used
to trace the propagation of solar features ejected by the wind and
solar eruptions (coronal mass ejections). The FIP bias also helps us to
understand the formation of prominences, as it is a tracer for the solar
origin of prominence plasma. <BR /> Aims: This work aims to provide
elemental composition and FIP bias in quiescent solar prominences. This
is key information to link these features to remnants of solar eruptions
measured in-situ within the heliosphere and to constrain the coronal or
photospheric origin of prominence plasma. <BR /> Methods: We used the
differential emission measure technique to derive the FIP bias of two
prominences. Quiet Sun chromospheric and transition region data were
used to test the atomic data and lines formation processes. We used
lines from low stage of ionization of Si, S, Fe, C, N, O, Ni, Mg, and
Ne, constraining the FIP bias in the range 4.2 ≤ log T ≤ 5.8. We
adopted a density-dependent ionization equilibrium. <BR /> Results:
We showed that the two prominences have photospheric composition. We
confirmed a photospheric composition in the quiet Sun. We also
identified opacity and/or radiative excitation contributions to the
line formation of a few lines regularly observed in prominences. <BR />
Conclusions: With our results we thus provide important elements for
correctly interpreting the upcoming Solar Orbiter/SPICE spectroscopic
data and to constrain prominence formation.
---------------------------------------------------------
Title: Elemental composition in quiescent prominences
Authors: Parenti, Susanna; Del Zanna, Giulio; Vial, Jean-Claude
2019shin.confE.182P Altcode:
The first ionization potential (FIP) bias is currently used to trace the
propagation of solar features ejected by the wind and solar eruptions
(coronal mass ejections). The FIP bias also helps us to understand
the formation of prominences, as it is a tracer for the solar origin
of prominence plasma. This work aims to provide elemental composition
and FIP bias in quiescent solar prominences. This is key information
to link these features to remnants of solar eruptions measured in-situ
within the heliosphere and to constrain the coronal or photospheric
origin of prominence plasma. We used the differential emission measure
technique to derive the FIP bias of two prominences observed with
SOHO/SUMER. Quiet Sun chromospheric and transition region data were
used to test the atomic data and lines formation processes. We used
lines from low stage of ionization of Si, S, Fe, C, N, O, Ni, Mg, and
Ne, constraining the FIP bias in the range 4.2 < log T< 5.8. We
adopted a density-dependent ionization equilibrium. We showed that
the two prominences have photospheric composition. We also identified
opacity and/or radiative excitation contributions to the line formation
of a few lines regularly observed in prominences. With our results
we thus provide important elements for correctly interpreting the
upcoming Solar Orbiter/SPICE spectroscopic data and to constrain
prominence formation.
---------------------------------------------------------
Title: Solar data, dataproducts, and tools at MEDOC
Authors: Buchlin, Eric; Caminade, Stéphane; Dufourg, Nicolas;
Auchère, Frédéric; Baudin, Frédéric; Bocchialini, Karine;
Boumier, Patrick; Janvier, Miho; Parenti, Susanna; Alingery, Pablo;
Ballans, Hervé; Chane-Yook, Martine; Dexet, Marc; Mercier, Claude;
Poulleau, Gilles
2019EGUGA..2117362B Altcode:
MEDOC (Multi-Experiment Data and Operation Centre), initially created
as a European data and operation centre for the SOHO mission, has
grown with data from other solar physics space missions, from STEREO
to SDO. Derived data products such as DEM maps from SDO/AIA, synoptic
EUV intensity maps from SOHO/EIT, and catalogues of solar structures
are also automatically produced and redistributed. Both the data and
the derived data products are publicly available from web interfaces
and from programmatic interfaces (with clients for IDL and Python),
allowing classical data analysis as well as automatic queries, data
download, and processing to be made on large datasets.
---------------------------------------------------------
Title: The SDO AIA and HMI archive at MEDOC
Authors: Alingery, Pablo; Buchlin, Éric; Caminade, Stéphane; Ballans,
Hervé; Baudin, Frédéric; Parenti, Susanna; Bocchialini, Karine
2018csc..confE.113A Altcode:
MEDOC, created as the European data and operations center for SoHO,
hosts also data from STEREO, SDO, and various other solar physics
missions. The SDO archive at MEDOC represents more than 415TB of data,
and covers the full length of the mission. It includes aia.lev1 data at
a minimum cadence of 60s in the EUV channels (12s at specific periods of
interest), and most of the 720s-cadence HMI series. It is complemented
by a database of DEM maps derived from AIA. MEDOC provides a reliable,
convenient, and fast (especially for European users) access to these
SDO data, by a web interface and webservices. We also provide IDL
and Python clients to these webservices, allowing complex queries and
automated analyses on large datasets to be made.
---------------------------------------------------------
Title: Chemical fractionation in solar prominences
Authors: Parenti, Susanna; Vial, Jean-Claude; Del Zanna, Giulio
2018cosp...42E2585P Altcode:
The First Ionization Potential (FIP) fractionation of elemental
abundances in the solar atmosphere and solar wind is a known process
which appears to vary depending on the magnetic field property and
the dynamic nature of the environment. It is generally identified
by an increase of the low FIP elements (with FIP energy below 10 eV)
compared to the high FIP elements (with respect to the photospheric
values). For instance, the low FIP element abundance is enhanced
within active regions by about a factor of 3-4, with respect to
photospheric values. A similar property is measured in the slow
solar wind. This is one of the reasons why the FIP fractionation is
used as a proxy for identifying the solar wind source regions on the
Sun, a topic of particular relevance for the upcoming Solar Orbiter
mission.Cool, low-state ionized plasma and its composition have been
measured in-situ within interplanetary Coronal Mass Ejections (ICMEs)
in only a few cases. This cool plasma has been associated to remnants
of erupting prominences. However, this association is not confirmed,
because the measurement of the composition within prominence plasma is
very difficult and poorly known. The scope of this paper is to provide
a reliable measurement of elements composition and FIP fractionation in
a prominence using the available SOHO/SUMER dataset of the prominence
atlas presented in Parenti et. al 2005. Our investigation will consider
ions formed in the prominence-corona transition region, taking into
account possible density and opacity effects in the formation of the
spectral lines.
---------------------------------------------------------
Title: Search for predicted periodic flows in loops undergoing
thermal non-equilibrium
Authors: Pelouze, Gabriel; Parenti, Susanna; Bocchialini, Karine;
Soubrie, Elie; Auchere, Frederic; Froment, Clara
2018cosp...42E2623P Altcode:
Long-period intensity pulsations have been recently detected in
coronal loopswith EUV images of both SoHO/EIT (Auchère et al.,
2014) and SDO/AIA (Froment etal., 2015). These pulsations have
been interpreted as resulting from thermalnon-equilibrium (TNE),
thus providing a signature of a highly-stratified andquasi-constant
heating at the loops footpoints (Froment et al., 2017; Auchèreet al.,
2016). Depending on the adequacy between the geometry of the loop
andthe characteristics of the heating, this can result in either
complete (atchromospheric temperatures) or incomplete (> 1 MK)
condensation and evaporationcycles, that are responsible for the
observed intensity pulsations. Using 1Dhydrodynamic simulations,
Froment et al. (2017) were able to reproduce theobserved pulsations,
with incomplete condensation for the active region studiedin their
previous paper. The simulations also predict periodic plasma flowsalong
the loops footpoints, with velocities up to 40 km/s. We try to detect
these flows by using time series of spatially resolved spectrafrom
the EUV spectrometer Hinode/EIS. We systematically search for EIS
datasetsthat correspond to the observation of pulsation events among
the 3000+ thatwere detected in AIA data, between 2010 and 2016. For the
9 datasets that arefound, we derive series of Doppler velocity maps,
which allows us to track theevolution of the plasma velocity in the
loop over several pulsation periods. Wethen compare these data to the
results of previous simulations andobservations. However the expected
pulsations in velocity cannot be identifiedin any of the datasets that
we analysed. We demonstrate that line of sightambiguities, combined
with low signal to noise ratio or lack of time cadence,can explain
this non-detection.
---------------------------------------------------------
Title: Spectroscopy of Very Hot Plasma in Non-flaring Parts of a
Solar Limb Active Region: Spatial and Temporal Properties
Authors: Parenti, Susanna; del Zanna, Giulio; Petralia, Antonino;
Reale, Fabio; Teriaca, Luca; Testa, Paola; Mason, Helen E.
2017ApJ...846...25P Altcode: 2017arXiv170708445P
In this work we investigate the thermal structure of an off-limb
active region (AR) in various non-flaring areas, as it provides key
information on the way these structures are heated. In particular,
we concentrate on the very hot component (> 3 {MK}) as it is a
crucial element to distinguish between different heating mechanisms. We
present an analysis using Fe and Ca emission lines from both the
Solar Ultraviolet Measurement of Emitted Radiation (SUMER) on board
the Solar and Heliospheric Observatory (SOHO) and the EUV Imaging
Spectrometer (EIS) on board Hinode. A data set covering all ionization
stages from Fe x to Fe xix has been used for the thermal analysis
(both differential emission measure and emission measure, EM). Ca
xiv is used for the SUMER-EIS radiometric cross calibration. We show
that the very hot plasma is present and persistent almost everywhere
in the core of the limb AR. The off-limb AR is clearly structured in
Fe xviii. Almost everywhere, the EM analysis reveals plasma at 10 MK
(visible in Fe xix emission), which is down to 0.1% of EM of the main
3 {MK} plasma. We estimate the power-law index of the hot tail of
the EM to be between -8.5 and -4.4. However, the question about the
possible existence of a small minor peak at around 10 {MK} remains
open. The absence in some part of the AR of the Fe xix and Fe xxiii
lines (which fall into our spectral range) enables us to determine
an upper limit on the EM at these temperatures. Our results include
a new Ca xiv 943.59 Å atomic model.
---------------------------------------------------------
Title: The SDO AIA and HMI archive at MEDOC
Authors: Alingery, P.; Wang, G.; Buchlin, E.; Caminade, S.; Ballans,
H.; Baudin, F.; Parenti, S.
2016usc..confE..97A Altcode:
MEDOC, created as the European data and operations center for SoHO,
hosts also data from STEREO, SDO, and various other solar physics
missions. The SDO archive at MEDOC represents more than 250TB of data,
and covers the full length of the mission. It includes aia.lev1 data at
a minimum cadence of 60s in the EUV channels (12s at specific periods of
interest), and most of the 720s-cadence HMI series. It is complemented
by a database of DEM maps derived from AIA, that will be presented at
the mini-workshop on thermal diagnostics. MEDOC provides a reliable,
convenient, and fast (especially for European users) access to these
SDO data, by a web interface and webservices. We also provide IDL
and Python clients to these webservices, allowing complex queries and
automated analyses on large datasets to be made.
---------------------------------------------------------
Title: GAIA-DEM: a database providing AIA/SDO DEM maps
Authors: Guennou, C.; Auchère, F.; Bocchialini, F.; Soubrié, E.;
Mercier, C.; Parenti, S.; Alingery, P.
2016usc..confE.108G Altcode:
The Gaussian AIA DEm Maps (GAIA-DEM) database at MEDOC (IAS) provides
through a simple and intuitive web interface DEM inversions of the
SDO/AIA data, computed every 30min. The Gaussian approximation is used
to describe the main features of the true DEM(log T) by its first
moments. For each date, maps of the three Gaussian fit parameters
(central temperature, total emission measure and Gaussian width) and
of the chi^2 are available in FITS format. Users can preview the maps
before downloading them. In addition, users can display the initial
SDO/AIA images using Helioviewer, and query the database through
webservices accessible from IDL and Python clients. This presentation
is for the "Thermal Diagnostics with SDO/AIA" mini-workshop.
---------------------------------------------------------
Title: The SPICE Spectral Imager on Solar Orbiter: Linking the Sun
to the Heliosphere
Authors: Fludra, Andrzej; Haberreiter, Margit; Peter, Hardi; Vial,
Jean-Claude; Harrison, Richard; Parenti, Susanna; Innes, Davina;
Schmutz, Werner; Buchlin, Eric; Chamberlin, Phillip; Thompson,
William; Gabriel, Alan; Morris, Nigel; Caldwell, Martin; Auchere,
Frederic; Curdt, Werner; Teriaca, Luca; Hassler, Donald M.; DeForest,
Craig; Hansteen, Viggo; Carlsson, Mats; Philippon, Anne; Janvier, Miho;
Wimmer-Schweingruber, Robert; Griffin, Douglas; Davila, Joseph; Giunta,
Alessandra; Waltham, Nick; Eccleston, Paul; Gottwald, Alexander;
Klein, Roman; Hanley, John; Walls, Buddy; Howe, Chris; Schuehle, Udo
2016cosp...41E.607F Altcode:
The SPICE (Spectral Imaging of the Coronal Environment) instrument is
one of the key remote sensing instruments onboard the upcoming Solar
Orbiter Mission. SPICE has been designed to contribute to the science
goals of the mission by investigating the source regions of outflows
and ejection processes which link the solar surface and corona to the
heliosphere. In particular, SPICE will provide quantitative information
on the physical state and composition of the solar atmosphere
plasma. For example, SPICE will access relative abundances of ions to
study the origin and the spatial/temporal variations of the 'First
Ionization Potential effect', which are key signatures to trace the
solar wind and plasma ejections paths within the heliosphere. Here we
will present the instrument and its performance capability to attain the
scientific requirements. We will also discuss how different observation
modes can be chosen to obtain the best science results during the
different orbits of the mission. To maximize the scientific return of
the instrument, the SPICE team is working to optimize the instrument
operations, and to facilitate the data access and their exploitation.
---------------------------------------------------------
Title: Solar abundances with the SPICE spectral imager on Solar
Orbiter
Authors: Giunta, Alessandra; Haberreiter, Margit; Peter, Hardi;
Vial, Jean-Claude; Harrison, Richard; Parenti, Susanna; Innes, Davina;
Schmutz, Werner; Buchlin, Eric; Chamberlin, Phillip; Thompson, William;
Bocchialini, Karine; Gabriel, Alan; Morris, Nigel; Caldwell, Martin;
Auchere, Frederic; Curdt, Werner; Teriaca, Luca; Hassler, Donald M.;
DeForest, Craig; Hansteen, Viggo; Carlsson, Mats; Philippon, Anne;
Janvier, Miho; Wimmer-Schweingruber, Robert; Griffin, Douglas; Baudin,
Frederic; Davila, Joseph; Fludra, Andrzej; Waltham, Nick; Eccleston,
Paul; Gottwald, Alexander; Klein, Roman; Hanley, John; Walls, Buddy;
Howe, Chris; Schuehle, Udo; Gyo, Manfred; Pfiffner, Dany
2016cosp...41E.681G Altcode:
Elemental composition of the solar atmosphere and in particular
abundance bias of low and high First Ionization Potential (FIP)
elements are a key tracer of the source regions of the solar wind. These
abundances and their spatio-temporal variations, as well as the other
plasma parameters , will be derived by the SPICE (Spectral Imaging
of the Coronal Environment) EUV spectral imager on the upcoming
Solar Orbiter mission. SPICE is designed to provide spectroheliograms
(spectral images) using a core set of emission lines arising from ions
of both low-FIP and high-FIP elements. These lines are formed over
a wide range of temperatures, enabling the analysis of the different
layers of the solar atmosphere. SPICE will use these spectroheliograms
to produce dynamic composition maps of the solar atmosphere to be
compared to in-situ measurements of the solar wind composition of
the same elements (i.e. O, Ne, Mg, Fe). This will provide a tool to
study the connectivity between the spacecraft (the Heliosphere) and
the Sun. We will discuss the SPICE capabilities for such composition
measurements.
---------------------------------------------------------
Title: Spectral Diagnostics of Cool Prominence and PCTR Optically
Thin Plasmas
Authors: Parenti, Susanna
2015ASSL..415...61P Altcode:
This chapter is dedicated to introduce information we can derive from
optically thin emission of prominences plasma. This emission comes
mostly from the interface region with the corona, the prominence-corona
transition region, and it is observable in the UV-EUV wavebands. After
a general introduction to the formation of the optically thin emission,
we present the diagnostics methods which are used to infer the thermal
properties of the emitting plasma under isothermal and multi-thermal
hypothesis. We then describe a diagnostics technique to infer the
electron density. For each method presented we give advantages and
limitations, together with the main results. We then discuss the
diagnostics at small, unresolved scales introducing the filling factor
and conclude with some final remarks.
---------------------------------------------------------
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.
---------------------------------------------------------
Title: Solar Prominences: Observations
Authors: Parenti, Susanna
2014LRSP...11....1P Altcode:
Solar prominences are one of the most common features of the solar
atmosphere. They are found in the corona but they are one hundred
times cooler and denser than the coronal material, indicating
that they are thermally and pressure isolated from the surrounding
environment. Because of these properties they appear at the limb as
bright features when observed in the optical or the EUV cool lines. On
the disk they appear darker than their background, indicating the
presence of a plasma absorption process (in this case they are called
filaments). Prominence plasma is embedded in a magnetic environment
that lies above magnetic inversion lines, denoted a filament channel.
---------------------------------------------------------
Title: MASC: Magnetic Activity of the Solar Corona
Authors: Auchere, Frederic; Fineschi, Silvano; Gan, Weiqun; Peter,
Hardi; Vial, Jean-Claude; Zhukov, Andrei; Parenti, Susanna; Li, Hui;
Romoli, Marco
2014cosp...40E.149A Altcode:
We present MASC, an innovative payload designed to explore the magnetic
activity of the solar corona. It is composed of three complementary
instruments: a Hard-X-ray spectrometer, a UV / EUV imager, and a Visible
Light / UV polarimetric coronagraph able to measure the coronal magnetic
field. The solar corona is structured in magnetically closed and
open structures from which slow and fast solar winds are respectively
released. In spite of much progress brought by two decades of almost
uninterrupted observations from several space missions, the sources and
acceleration mechanisms of both types are still not understood. This
continuous expansion of the solar atmosphere is disturbed by sporadic
but frequent and violent events. Coronal mass ejections (CMEs) are
large-scale massive eruptions of magnetic structures out of the corona,
while solar flares trace the sudden heating of coronal plasma and the
acceleration of electrons and ions to high, sometimes relativistic,
energies. Both phenomena are most probably driven by instabilities
of the magnetic field in the corona. The relations between flares
and CMEs are still not understood in terms of initiation and energy
partition between large-scale motions, small-scale heating and
particle acceleration. The initiation is probably related to magnetic
reconnection which itself results magnetic topological changes due to
e.g. flux emergence, footpoints motions, etc. Acceleration and heating
are also strongly coupled since the atmospheric heating is thought to
result from the impact of accelerated particles. The measurement of
both physical processes and their outputs is consequently of major
importance. However, despite its fundamental importance as a driver
for the physics of the Sun and of the heliosphere, the magnetic field
of our star’s outer atmosphere remains poorly understood. This
is due in large part to the fact that the magnetic field is a very
difficult quantity to measure. Our knowledge of its strength and
orientation is primarily based on extrapolations from photospheric
observations, not from direct measurements. These extrapolations
require strong assumptions on critical but unobserved quantities and
thus fail to accurately reproduce the complex topologies inferred
from remote-sensing observations of coronal structures in white
light, EUV, and X-rays. Direct measurements of the coronal magnetic
field are also clearly identified by the international heliophysics
community as a key element susceptible to lead to major breakthroughs
in the understanding of our star. MASC is thus designed to answer
the following top-level scientific questions: 1. What is the global
magnetic field configuration in the corona? 2. What is the role of
the magnetic field in the triggering of flares and CMEs? 3. What is
the role of the magnetic field in the acceleration mechanisms of the
solar winds? 4. What is the energy spectrum and in particular what are
the highest energies to which charged particles can be accelerated in
the solar corona? MASC will address these fundamental questions with
a suite of instruments composed of an X-ray spectrometer, a UV / EUV
imager, and a coronagraph working in the visible and at Lyman alpha. The
spectrometer will provide information on the energetics of solar flares,
in particular at very high energies of accelerated particles. The
UV / EUV imager will provide constraints on the temperature of the
flaring and non-flaring corona. The coronagraph will provide the number
density of free electrons in the corona, maps of the outflow velocity
of neutral hydrogen, and measurements of the coronal magnetic field,
via the Hanle effect. These measurements will be performed at all
steps of the flare-CME processes, thus providing a detailed picture
of the solar coronal dynamics in the quiet and eruptive periods.
---------------------------------------------------------
Title: On the nature of the prominence - corona transition region
Authors: Parenti, Susanna; Vial, Jean-Claude
2014IAUS..300...69P Altcode:
Due to the complexity of their environment, prominences properties are
still a matter of controversy. Prominences cool and dense plasma is
suspended in the hot corona by a magnetic structure poorly known. Their
thermal insulation from the corona results in a thin geometrical
interface called prominence-corona-transition-region (PCTR). Here we
will review the main properties of such a region as derived primarily
from observations. We will introduce the thermal structure properties,
describe the fine structure together with the Doppler-shift and width
properties of lines of the emitting plasma. We will introduce the
proposed interpretations of such observations and the limits of our
knowledge imposed by the present instrumentation. We will conclude
with a perspective for the future observations of the PCTR.
---------------------------------------------------------
Title: Can the Differential Emission Measure Constrain the Timescale
of Energy Deposition in the Corona?
Authors: Guennou, C.; Auchère, F.; Klimchuk, J. A.; Bocchialini,
K.; Parenti, S.
2013ApJ...774...31G Altcode: 2013arXiv1306.3114G
In this paper, the ability of the Hinode/EIS instrument to detect
radiative signatures of coronal heating is investigated. Recent
observational studies of active region cores suggest that both
the low and high frequency heating mechanisms are consistent with
observations. Distinguishing between these possibilities is important
for identifying the physical mechanism(s) of the heating. The
differential emission measure (DEM) tool is one diagnostic that
allows us to make this distinction, through the amplitude of the
DEM slope coolward of the coronal peak. It is therefore crucial to
understand the uncertainties associated with these measurements. Using
proper estimations of the uncertainties involved in the problem
of DEM inversion, we derive confidence levels on the observed DEM
slope. Results show that the uncertainty in the slope reconstruction
strongly depends on the number of lines constraining the slope. Typical
uncertainty is estimated to be about ±1.0 in the more favorable cases.
---------------------------------------------------------
Title: Solar activity and its evolution across the corona: recent
advances
Authors: Zuccarello, Francesca; Balmaceda, Laura; Cessateur, Gael;
Cremades, Hebe; Guglielmino, Salvatore L.; Lilensten, Jean; Dudok
de Wit, Thierry; Kretzschmar, Matthieu; Lopez, Fernando M.; Mierla,
Marilena; Parenti, Susanna; Pomoell, Jens; Romano, Paolo; Rodriguez,
Luciano; Srivastava, Nandita; Vainio, Rami; West, Matt; Zuccarello,
Francesco P.
2013JSWSC...3A..18Z Altcode:
Solar magnetism is responsible for the several active phenomena that
occur in the solar atmosphere. The consequences of these phenomena on
the solar-terrestrial environment and on Space Weather are nowadays
clearly recognized, even if not yet fully understood. In order to shed
light on the mechanisms that are at the basis of the Space Weather,
it is necessary to investigate the sequence of phenomena starting in
the solar atmosphere and developing across the outer layers of the Sun
and along the path from the Sun to the Earth. This goal can be reached
by a combined multi-disciplinary, multi-instrument, multi-wavelength
study of these phenomena, starting with the very first manifestation
of solar active region formation and evolution, followed by explosive
phenomena (i.e., flares, erupting prominences, coronal mass ejections),
and ending with the interaction of plasma magnetized clouds expelled
from the Sun with the interplanetary magnetic field and medium. This
wide field of research constitutes one of the main aims of COST Action
ES0803: Developing Space Weather products and services in Europe. In
particular, one of the tasks of this COST Action was to investigate
the Progress in Scientific Understanding of Space Weather. In this
paper we review the state of the art of our comprehension of some
phenomena that, in the scenario outlined above, might have a role on
Space Weather, focusing on the researches, thematic reviews, and main
results obtained during the COST Action ES0803.
---------------------------------------------------------
Title: SDO/AIA Prominence physical conditions
Authors: Schmieder, B.; Parenti, S.; Dudik, J.; Aulanier, G.; Heinzel,
P.; Zapior, M.; Golub, L.
2013enss.confE..27S Altcode:
SDO/AIA has carried out continuous observations of prominences in
multiple wavelengths, with high spatial and temporal resolution. These
data provide us an opportunity to understand the physical conditions
and dynamics of prominences. The surprising brightness of prominences
in some coronal lines has been well explained by the presence of
transition region lines in the bandpass of the filters (171 A, 131 A),
a result that leads us to revise our model of the transition region
of prominences and to consider a relatively dense transition region in
some prominence evolutionary phases or in some viewing orientation. An
additional aspect of prominence dynamics will be presented with a new
quasi-static MHD model proposed for bubbles and plumes. We propose
an alternative to the interpretation that thermal instabilities are
responsible for the formation of bubbles. The bubbles are found to
correspond to magnetic separatrices formed by emerging magnetic field
close to prominence footpoints.
---------------------------------------------------------
Title: Can the Differential Emission Measure diagnostic be used to
constrain the timescale of energy deposition in the corona?
Authors: Guennou, C.; Auchère, F.; Klimchuk, J. A.; Bocchialini,
K.; Parenti, S.
2013enss.confE..34G Altcode:
Differential emission measure (DEM) analysis is a widespread tool used
to diagnose the thermal properties of coronal plasmas. The slope of
the DEM distribution coolward of the coronal peak (near 3-4MK in active
regions) can be used to diagnose the timescale for the energy deposition
repeating on a given magnetic strand. Recent AR studies suggest that
some active region cores are consistent with low frequency heating
mechanisms, where the plasma cools completely before being reheated,
while other show consistency with high frequency energy deposition,
where rapid reheating causes the temperature to fluctuate about
a particular value. Distinguishing between these possibilities is
important for identifying the physical mechanism of the heating. It is
therefore crucial to understand the uncertainties in measurements of
observed DEM slopes. In this work, based on a probabilistic approach
and Monte Carlo simulations, we carefully assess the errors in the
slopes determined from EIS data. We consider both the random errors due
to photon counting statistics, and the systematic errors associated
with uncertainties in atomic physics and instrument calibration. The
technique developed provides all the solutions consistent with the data
and their associated probabilities. We demonstrate how the quality
and the accuracy of the inversion are affected by the presence of
noises and systematic errors, and we characterise the quality of the
DEM inversion and its statistical properties. From these results,
estimation of the uncertainties in the reconstructed slopes can be
derived, thereby allowing a proper interpretation of the degree of
agreement between observations and heating model predictions.
---------------------------------------------------------
Title: MEDIA : MEDoc Interface for AIA
Authors: Alingery, P.; Soubrié, E.; Auchère, F.; Bocchialini, K.;
Boignard, J. P.; Buchlin, E.; Malappert, J. C.; Parenti, S.
2013enss.confE..88A Altcode:
MEDOC, the space solar data center at Orsay
(http://www.ias.u-psud.fr/medoc) is now providing a new web access
to the AIA/SDO level 1 images. This interface has the advantage of
being simple, intuitive, very stable and fast. The full resolution
4k x 4k AIA level 1 images archived at MEDOC are downloaded from
upstream DRMS nodes with a 1 minute cadence at all wavelengths. The
dataset will be kept online on a redundant archive for the whole SDO
mission duration. The FITS files are accessible via an user friendly
web interface (http://medoc-sdo.ias.u-psud.fr) that allows users
to request data by selecting a date range, the desired wavelengths
and a sampling rate (choosing a cadence from 1 minute to 1 day). For
each file, users can preview the image (using the Helioviewer tool)
or display the header information before downloading the FITS files
(with or without Rice-compression). This web interface was built
using Sitools2, a tool developed by CNES, the French space agency, and
supports most browsers. For more advanced users, a Search/Get Python
module is also available at http://sdo.ias.u-psud.fr/python. The users
can use it to build more complex yet more powerful queries. We encourage
everyone in Europe and beyond to use these new services!
---------------------------------------------------------
Title: On the Accuracy of the Differential Emission Measure
Diagnostics of Solar Plasmas. Application to SDO/AIA. II. Multithermal
Plasmas
Authors: Guennou, C.; Auchère, F.; Soubrié, E.; Bocchialini, K.;
Parenti, S.; Barbey, N.
2012ApJS..203...26G Altcode: 2012arXiv1210.2302G
Differential emission measure (DEM) analysis is one of the most
used diagnostic tools for solar and stellar coronae. Being an inverse
problem, it has limitations due to the presence of random and systematic
errors. We present in this series of papers an analysis of the
robustness of the inversion in the case of SDO/AIA observations. We
completely characterize the DEM inversion and its statistical
properties, providing all the solutions consistent with the data along
with their associated probabilities, and a test of the suitability of
the assumed DEM model. While Paper I focused on isothermal conditions,
we now consider multithermal plasmas and investigate both isothermal and
multithermal solutions. We demonstrate how the ambiguity between noises
and multithermality fundamentally limits the temperature resolution
of the inversion. We show that if the observed plasma is multithermal,
isothermal solutions tend to cluster on a constant temperature whatever
the number of passbands or spectral lines. The multithermal solutions
are also found to be biased toward near-isothermal solutions around 1
MK. This is true even if the residuals support the chosen DEM model,
possibly leading to erroneous conclusions on the observed plasma. We
propose tools for identifying and quantifying the possible degeneracy
of solutions, thus helping the interpretation of DEM inversion.
---------------------------------------------------------
Title: On the Accuracy of the Differential Emission Measure
Diagnostics of Solar Plasmas. Application to SDO/AIA. I. Isothermal
Plasmas
Authors: Guennou, C.; Auchère, F.; Soubrié, E.; Bocchialini, K.;
Parenti, S.; Barbey, N.
2012ApJS..203...25G Altcode: 2012arXiv1210.2304G
Differential emission measure (DEM) analysis is a major diagnostic
tool for stellar atmospheres. However, both its derivation and its
interpretation are notably difficult because of random and systematic
errors, and the inverse nature of the problem. We use simulations with
simple thermal distributions to investigate the inversion properties
of SDO/AIA observations of the solar corona. This allows a systematic
exploration of the parameter space, and using a statistical approach
the respective probabilities of all the DEMs compatible with the
uncertainties can be computed. Following this methodology, several
important properties of the DEM inversion, including new limitations,
can be derived and presented in a very synthetic fashion. In this first
paper, we describe the formalism and we focus on isothermal plasmas
as building blocks to understand the more complex DEMs studied in the
second paper. The behavior of the inversion of AIA data being thus
quantified, and we provide new tools to properly interpret the DEM. We
quantify the improvement of the isothermal inversion with six AIA bands
compared to previous EUV imagers. The maximum temperature resolution
of AIA is found to be 0.03 log T<SUB>e</SUB> , and we derive a rigorous
test to quantify the compatibility of observations with the isothermal
hypothesis. However, we demonstrate limitations in the ability of AIA
alone to distinguish different physical conditions.
---------------------------------------------------------
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: Plasma Diagnostics and Magnetic Complexity of a Post-Flare
Active Region with Hinode/XRT: Spatial and Temporal Evolution
Authors: Parenti, S.; Reale, F.; Reeves, K. K.
2012ASPC..454..291P Altcode:
Flares are localized phenomena in active regions, but the magnetic
and plasma responses may propagate to a larger area. In this work we
investigate the temporal evolution of a flare in an active region
with particular attention to the morphological details, and to the
temperature and emission measure diagnostics allowed by Hinode/XRT.
---------------------------------------------------------
Title: On the Thermal diagnostics of Coronal Loops with SDO/AIA
Authors: Guennou, Chloe; Parenti, Susanna; Bocchialini, Karine;
Soubrie, Elie; Auchere, Frederic; Barbey, Nicolas
2012cosp...39..675G Altcode: 2012cosp.meet..675G
With simultaneous observations in 6 coronal bands, AIA has the
capability to provide spectral diagnostics over an extended field of
view at high resolution and high cadence. Therefore, DEM diagnostics of
coronal loops can in principle be performed routinely for statistical
studies. We investigate here the pertinence of the DEM analysis with
AIA. The inevitable presence of noises and uncertainties, incompleteness
of the atomic physics databases lead to notable difficulties in the
inversion process. The complications involved in the derivation of
the DEM are one of the reasons of the controversial results regarding
the thermal structure and thus the heating scenario of the coronal
loops. The purpose of this work, based on a probabilistic approach, is
precisely to investigate the properties of the solutions, providing a
quantification of the DEM inversion problem robustness. The technique
relies on Monte Carlo simulations of observed intensities in the six
AIA coronal bands. The comparison between the known inputs and the
inversion results allows us to determine the degree of robustness. This
approach provides all the solutions consistent with the data along with
their associated probabilities, as well as a test of the validity of
the assumptions made on the DEM shape. Applications to SDO/AIA coronal
loops data are presented.
---------------------------------------------------------
Title: Prominences observations with SDO/AIA
Authors: Parenti, Susanna; Schmieder, Brigitte; Golub, Leon; Heinzel,
Petr
2012cosp...39.1447P Altcode: 2012cosp.meet.1447P
The Prominence-Corona-Transition-Region (PCTR) plays a key role in
the thermal and pressure equilibrium of prominences. However, several
open issues limit our knowledge of this important interface. Among
them we find the thermal structure and the maximum temperature of
its emitting plasma. This work is a new step toward resolving these
issues. By noting that prominences may be observed in emission in
the 171 and 131 SDO/AIA images, while they are seen in absorption in
others (e.g. 193) we investigate the temperature content of these
channels. Using the CHIANTI atomic database and previously derived
prominence DEMs, we built synthetic spectra in these AIA channels to
establish the main contributors. We find that the Fe IX line always
dominates the 171 band, even in absence of a coronal plasma, while
the 131 channel is dominated by Fe VIII. Our conclusion is that the
PCTR reaches, at least, 4x 10^5 K.
---------------------------------------------------------
Title: On the Nature of Prominence Emission Observed by SDO/AIA
Authors: Parenti, S.; Schmieder, B.; Heinzel, P.; Golub, L.
2012ApJ...754...66P Altcode: 2012arXiv1205.5460P
The prominence-corona transition region (PCTR) plays a key role in the
thermal and pressure equilibrium of solar prominences. Our knowledge
of this interface is limited and several major issues remain open,
including the thermal structure and, in particular, the maximum
temperature of the detectable plasma. The high signal-to-noise
ratio of images obtained by the Atmospheric Imaging Assembly (AIA)
on NASA's Solar Dynamics Observatory clearly shows that prominences
are often seen in emission in the 171 and 131 bands. We investigate the
temperature sensitivity of these AIA bands for prominence observations,
in order to infer the temperature content in an effort to explain the
emission. Using the CHIANTI atomic database and previously determined
prominence differential emission measure distributions, we build
synthetic spectra to establish the main emission-line contributors
in the AIA bands. We find that the Fe IX line always dominates
the 171 band, even in the absence of plasma at >10<SUP>6</SUP> K
temperatures, while the 131 band is dominated by Fe VIII. We conclude
that the PCTR has sufficient plasma emitting at >4 × 10<SUP>5</SUP>
K to be detected by AIA.
---------------------------------------------------------
Title: Radio observations of weak energy releases in the solar corona
Authors: Ramesh, Rengaswamy; Parenti, Susanna
2012cosp...39.1568R Altcode: 2012cosp.meet.1568R
..
---------------------------------------------------------
Title: Comparing Radiative signatures of conductive heating in
coronal loops
Authors: West, Matthew; Parenti, Susanna
2012cosp...39.2149W Altcode: 2012cosp.meet.2149W
No abstract at ADS
---------------------------------------------------------
Title: On the Visibility of Solar Prominences in SDO/AIA Channels
Authors: Heinzel, P.; Schmieder, B.; Parenti, S.; Golub, L.
2012ASPC..456...75H Altcode:
Prominences in EUV lines are observed as dark structures over the
limb due absorption and emission blocking mechanisms. However, at 171
Å is observed emission in prominences with TRACE and SDO/AIA, and
it is believed to be due to the prominence-corona transition region
(PCTR) emitting in cool lines. To check this, we use the Differential
Emission Measure (DEM) recently obtained for quiescent prominences
using SOHO/SUMER spectra (Parenti and Vial 2007) and compute the
synthetic spectra in selected AIA channels. We then compare 171 Å and
195 Å channels and derive conclusions concerning the PCTR emissivity,
as well well as the absorption and blocking. The emission seen in the
171 Å channel can be used to better constrain prominence DEM curves.
---------------------------------------------------------
Title: Stability of thermal modes in cool prominence plasmas
Authors: Soler, R.; Ballester, J. L.; Parenti, S.
2012A&A...540A...7S Altcode: 2012arXiv1201.4668S
Magnetohydrodynamic thermal modes may play an important role
in the formation, plasma condensation, and evolution of solar
prominences. Unstable thermal modes due to unbalance between
radiative losses and heating can lead to rapid plasma cooling and
condensation. An accurate description of the radiative loss function
is therefore crucial for this process. We study the stability of
thermal modes in unbounded and uniform plasmas with properties akin to
those in solar prominences. Effects of partial ionization are taken
into account. Three different parametrizations of the radiative loss
function are used. By means of a normal mode analysis, we investigate
linear nonadiabatic perturbations superimposed on the equilibrium
state. We find an approximate instability criterion for thermal
modes, while the exact linear growth rate is obtained by numerically
solving the general dispersion relation. The stability of thermal
disturbances is compared for the three different loss functions that
we consider. Using up-to-date computations of radiative losses derived
from the CHIANTI atomic database, we find that thermal modes may be
unstable in prominences for lower temperatures than those predicted
with previously existing loss functions. Thermal instability can take
place for temperatures as low as about 15 000 K. The obtained linear
growth rates indicate that this instability might have a strong impact
on the dynamics and evolution of cool prominence condensations.
---------------------------------------------------------
Title: Solar magnetism eXplorer (SolmeX). Exploring the magnetic
field in the upper atmosphere of our closest star
Authors: Peter, Hardi; Abbo, L.; Andretta, V.; Auchère, F.; Bemporad,
A.; Berrilli, F.; Bommier, V.; Braukhane, A.; Casini, R.; Curdt,
W.; Davila, J.; Dittus, H.; Fineschi, S.; Fludra, A.; Gandorfer, A.;
Griffin, D.; Inhester, B.; Lagg, A.; Landi Degl'Innocenti, E.; Maiwald,
V.; Sainz, R. Manso; Martínez Pillet, V; Matthews, S.; Moses, D.;
Parenti, S.; Pietarila, A.; Quantius, D.; Raouafi, N. -E.; Raymond, J.;
Rochus, P.; Romberg, O.; Schlotterer, M.; Schühle, U.; Solanki, S.;
Spadaro, D.; Teriaca, L.; Tomczyk, S.; Trujillo Bueno, J.; Vial, J. -C.
2012ExA....33..271P Altcode: 2011arXiv1108.5304P; 2011ExA...tmp..134P
The magnetic field plays a pivotal role in many fields of
Astrophysics. This is especially true for the physics of the solar
atmosphere. Measuring the magnetic field in the upper solar atmosphere
is crucial to understand the nature of the underlying physical
processes that drive the violent dynamics of the solar corona—that
can also affect life on Earth. SolmeX, a fully equipped solar space
observatory for remote-sensing observations, will provide the first
comprehensive measurements of the strength and direction of the
magnetic field in the upper solar atmosphere. The mission consists
of two spacecraft, one carrying the instruments, and another one in
formation flight at a distance of about 200 m carrying the occulter to
provide an artificial total solar eclipse. This will ensure high-quality
coronagraphic observations above the solar limb. SolmeX integrates two
spectro-polarimetric coronagraphs for off-limb observations, one in
the EUV and one in the IR, and three instruments for observations on
the disk. The latter comprises one imaging polarimeter in the EUV for
coronal studies, a spectro-polarimeter in the EUV to investigate the low
corona, and an imaging spectro-polarimeter in the UV for chromospheric
studies. SOHO and other existing missions have investigated the emission
of the upper atmosphere in detail (not considering polarization),
and as this will be the case also for missions planned for the near
future. Therefore it is timely that SolmeX provides the final piece of
the observational quest by measuring the magnetic field in the upper
atmosphere through polarimetric observations.
---------------------------------------------------------
Title: Synthetic differential emission measure curves of prominence
fine structures. II. The SoHO/SUMER prominence of 8 June 2004
Authors: Gunár, S.; Parenti, S.; Anzer, U.; Heinzel, P.; Vial, J. -C.
2011A&A...535A.122G Altcode:
<BR /> Aims: This study is the first attempt to combine the prominence
observations in Lyman, UV, and EUV lines with the determination of the
prominence differential emission measure derived using two different
techniques, one based on the inversion of the observed UV and EUV lines
and the other employing 2D non-LTE prominence fine-structure modeling
of the Lyman spectra. <BR /> Methods: We use a trial-and-error method
to derive the 2D multi-thread prominence fine-structure model producing
synthetic Lyman spectra in good agreement with the observations. We then
employ a numerical method to perform the forward determination of the
DEM from 2D multi-thread models and compare the synthetic DEM curves
with those derived from observations using inversion techniques. <BR
/> Results: A set of available observations of the June 8, 2004
prominence allows us to determine the range of input parameters, which
contains models producing synthetic Lyman spectra in good agreement
with the observations. We select three models, which represent this
parametric-space area well and compute the synthetic DEM curves for
multi-thread realizations of these models. The synthetic DEM curves
of selected models are in good agreement with the DEM curves derived
from the observations. <BR /> Conclusions: We show that the evaluation
of the prominence fine-structure DEM complements the analysis of the
prominence hydrogen Lyman spectra and that its combination with the
detailed radiative-transfer modeling of prominence fine structures
provides a useful tool for investigating the prominence temperature
structure from the cool core to the prominence-corona transition region.
---------------------------------------------------------
Title: Automated detection of filaments in SDO data
Authors: Buchlin, É.; Mercier, C.; Engin, S.; Parenti, S.; Vial,
J. -C.
2010sf2a.conf..297B Altcode:
Solar eruption can eject billions of tons of plasma to the
interplanetary space, with geophysical effects and impacts on human
activities. The time constraints for space weather application as well
as the huge volume of data that needs to be analyzed, especially since
the launch of SDO, imply that the detection of solar filaments and their
eruptions must be automated. Most current detection codes use Hα data,
which are not available frequently enough for these applications. We
present a new detection code that we have developed at IAS and that uses
the high spatial and temporal-resolution SDO/AIA He II 30.4 nm data.
---------------------------------------------------------
Title: An iterative method in a probabilistic approach to the
spectral inverse problem. Differential emission measure from line
spectra and broadband data
Authors: Goryaev, F. F.; Parenti, S.; Urnov, A. M.; Oparin, S. N.;
Hochedez, J. -F.; Reale, F.
2010A&A...523A..44G Altcode: 2010arXiv1010.5170G
Context. Inverse problems are of great importance in astrophysics,
e.g., for deriving information about the physical characteristics
of hot optically thin plasma sources from their extreme ultraviolet
and X-ray spectra. <BR /> Aims: We describe and test an iterative
method developed within the framework of a probabilistic approach to
the spectral inverse problem for determining the thermal structures
of the emitting plasma. We also demonstrate applications of this
method to both high resolution line spectra and broadband imaging
data. <BR /> Methods: Our so-called Bayesian iterative method (BIM)
is an iterative procedure based on Bayes' theorem and is used to
reconstruct differential emission measure (DEM) distributions. <BR />
Results: To demonstrate the abilities of the BIM, we performed various
numerical tests and model simulations establishing its robustness and
usefulness. We then applied the BIM to observable data for several
active regions (AR) previously analyzed with other DEM diagnostic
techniques: both SUMER/SOHO (Landi & Feldman 2008, ApJ, 672, 674)
and SPIRIT/CORONAS-F (Shestov et al. 2010, Astron. Lett., 36, 44)
line spectra data, and XRT/Hinode (Reale et al. 2009, ApJ, 698, 756)
broadband imaging data. The BIM calculations confirmed the main results
for SUMER/SOHO data showing very good quantitative agreement between
both DEMs at log T ≈ 6.5 (T is the temperature in units of Kelvin)
and a slight shift for two maxima at lower temperatures with ≈30-50%
difference in the DEM values for the coolest peak. For the SPIRIT data,
we revised and validated AR DEM results including the inference of hot
plasma in ARs with an emission measure (EM) at temperatures ≈9-15 MK
comparable to the EM at ≈2-4 MK. In the case of XRT broadband data,
the BIM solutions provided evidence of hot plasma at temperatures ≈4-6
MK with EM up to ~30% as compared to that at ≈2-4 MK in a non-flaring
AR on 2006 November 12. <BR /> Conclusions: The BIM results show that
this method is an effective tool for determining the thermal structure
of emitting plasma and can be successfully used for the DEM analysis
of both line spectra and broadband imaging data. The BIM calculations
correlate with recent studies confirming the existence of hot plasma
in solar ARs. The BIM results also indicate that the coronal plasma may
have the continuous distributions predicted by the nanoflare paradigm.
---------------------------------------------------------
Title: Post-flare evolution of AR 10923 with Hinode/XRT
Authors: Parenti, S.; Reale, F.; Reeves, K. K.
2010A&A...517A..41P Altcode: 2010arXiv1010.3124P
Context. Flares are dynamic events which involve rapid changes in
coronal magnetic topology end energy release. Even if they may be
localized phenomena, the magnetic disturbance at their origin may
propagate and be effective in a larger part of the active region. <BR
/> Aims: We investigate the temporal evolution of a flaring active
region with respect to the loops morphology, the temperature,
and emission measure distributions. <BR /> Methods: We consider
Hinode/XRT data of a the 2006 November 12th C1.1 flare. We inspect
the evolution of the morphology of the flaring region also with the
aid of TRACE data. XRT filter ratios are used to derive temperature
and emission measure maps and evolution. <BR /> Results: The analyzed
flare includes several brightenings. We identify a coherent sequence
of tangled and relaxed loop structures before, during, and after the
brightenings. Although the thermal information is incomplete because of
pixel saturation at the flare peak, thermal maps show fine, evolving
spatial structuring. Temperature and emission measure variations show
up in great detail, and we are able to detect a secondary heating of
larger loops close to the proper flaring region. Finally we estimate the
amount of energy released in these flaring loops during the flare decay.
---------------------------------------------------------
Title: Physics of Solar Prominences: I—Spectral Diagnostics and
Non-LTE Modelling
Authors: Labrosse, N.; Heinzel, P.; Vial, J. -C.; Kucera, T.; Parenti,
S.; Gunár, S.; Schmieder, B.; Kilper, G.
2010SSRv..151..243L Altcode: 2010SSRv..tmp...34L; 2010arXiv1001.1620L
This review paper outlines background information and covers recent
advances made via the analysis of spectra and images of prominence
plasma and the increased sophistication of non-LTE ( i.e. when there is
a departure from Local Thermodynamic Equilibrium) radiative transfer
models. We first describe the spectral inversion techniques that have
been used to infer the plasma parameters important for the general
properties of the prominence plasma in both its cool core and the
hotter prominence-corona transition region. We also review studies
devoted to the observation of bulk motions of the prominence plasma and
to the determination of prominence mass. However, a simple inversion
of spectroscopic data usually fails when the lines become optically
thick at certain wavelengths. Therefore, complex non-LTE models become
necessary. We thus present the basics of non-LTE radiative transfer
theory and the associated multi-level radiative transfer problems. The
main results of one- and two-dimensional models of the prominences and
their fine-structures are presented. We then discuss the energy balance
in various prominence models. Finally, we outline the outstanding
observational and theoretical questions, and the directions for future
progress in our understanding of solar prominences.
---------------------------------------------------------
Title: The SDO data centre at IDOC/MEDOC in France
Authors: Parenti, Susanna; Bocchialini, Karine; Soubrie, Elie;
Auchere, Frederic; Ballans, Herv; Buchlin, Eric; Gabriel, Alan;
Mercier, Claude; Poulleau, Gilles; Vial, Jean-Claude
2010cosp...38.2888P Altcode: 2010cosp.meet.2888P
The IDOC/MEDOC centre at the Institut d'Astrophysique Spatiale (IAS,
Université Paris 11/CNRS) has a long experience in solar data archiving
and distribution, including almost 15 years of data from SOHO, STEREO
and TRACE. The center is now expanding its activity and becoming a
Pˆle Thématique Solaire of the CNES and INSU/CNRS. Part of the new
activities of the centre will be linked to the arrival of the enormous
volume of the new SDO data. The center will be one of the three European
centers to receive and redistribute the data to the community. It will
also be the only European site to permanently store about 10% of the
data (mainly from AIA). In continuity with its previous activities,
SDO data will be included in the data visualization tool FESTIVAL
and it will provide new services, like tools for the solar feature
identification (filaments, EUV intensity fluctuations). We will present
an overview of the facilities and activities of the centre in relation
to the SDO data.
---------------------------------------------------------
Title: Distributing and mining SDO data in Europe
Authors: Parenti, Susanna; Delouille, Véronique; Dalla, Silvia;
Bocchialini, Karine; Ballans, Herv; Boyes, David; Chapman, Steve;
Hochedez, Jean-François; Mampaey, Benjamin; March, Mike S.; Soubrie,
Elie; Walsh, Robert
2010cosp...38.2883P Altcode: 2010cosp.meet.2883P
The properties of the highly dynamic Sun will soon be revealed by the
newly launched SDO, with data provided by its three instruments: AIA,
HMI and EVE. This suite will produce, for the first time in solar
physics, a large volume of data, equivalent to about 1.5 Tb/day,
by observing the full disk Sun continuously at high cadence. A
backbone network of data centres has been established to handle
these data and redistribute them to Europe. The Royal Observatory
of Belgium (Belgium) will receive the entire flow directly from the
Harvard-Smithsonian Center for Astrophysics. This will next be further
redistributed to University of Central Lancashire (United Kingdom),
and to Institut d'Astrophysique Spatiale (France). These institutes
will also permanently store part of the data. With such huge data rate,
it is necessary to develop automated algorithms that scan the data
and extract information related to important events or features. The
European partners have gathered within an ISSI team on 'Mining and
exploiting the NASA Solar Dynamics Observatory data in Europe', a.k.a
the Soldyneuro project. One of the outputs from the ISSI team will be
to use the feature recognition algorithms to populate the Heliophysics
Events Knowledgebase (HEK) hosted by LMSAL, and provide a service as
added value to the local database centers.
---------------------------------------------------------
Title: DEM analysis for AIA/SDO EUV channels using a probabilistic
approach to the spectral inverse problem
Authors: Goryaev, Farid; Parenti, Susanna; Hochedez, Jean-François;
Urnov, Alexander
2010cosp...38.2867G Altcode: 2010cosp.meet.2867G
The Atmospheric Imaging Assembly (AIA) for the Solar Dynamics
Observatory (SDO) mis-sion is designed to observe the Sun from the
photosphere to the flaring corona. These data have to improve our
understanding of processes in the solar atmosphere. The differential
emis-sion measure (DEM) analysis is one of the main methods to derive
information about coronal optically thin plasma characteristics from
EUV and SXR emission. In this work we analyze AIA/SDO EUV channels to
estimate their ability to reconstruct DEM(T) distributions. We use
an iterative method (called Bayesian iterative method, BIM) within
the framework of a probabilistic approach to the spectral inverse
problem for determining the thermal structures of the emitting plasma
sources (Goryaev et al., submitted to AA). The BIM is an iterative
procedure based on Bayes' theorem and used for the reconstruction of
DEM profiles. Using the BIM algorithm we performed various numerical
tests and model simulations demonstrating abilities of our inversion
approach for DEM analysis with AIA/SDO EUV channels.
---------------------------------------------------------
Title: Differential emission measure for line spectra and broadband
data from the Bayesian iterative method
Authors: Goryaev, Farid; Parenti, Susanna; Urnov, Alexander; Oparin,
S. N.; Hochedez, Jean-François; Reale, Fabio
2010cosp...38.2901G Altcode: 2010cosp.meet.2901G
Inverse problems techniques allow deriving physical characteristics
of hot optically thin so-lar and stellar plasma from their extreme
ultraviolet and X-ray spectra. One of them, called Bayesian iterative
method (BIM), relies on a probabilistic Bayesian framework for the
spec-tral inverse problem, and reconstructs differential emission
measure (DEM) distributions. We present here the application of BIM
to both high resolution solar line spectra as well as to broadband
imaging data. To demonstrate its abilities, we present various
numerical tests and model simulations establishing robustness and
usefulness. We then apply BIM to several so-lar non flaring active
regions data previously analyzed with other techniques and instruments
(SOHO-SUMER, CORONAS/F-SPIRIT, and HINODE-XRT).
---------------------------------------------------------
Title: XRT Detection of Hot Plasma in Active Regions and Nanoflare
Heating
Authors: Reale, F.; Klimchuk, J. A.; Parenti, S.; Testa, P.
2009ASPC..415..256R Altcode:
Nanoflares occurring in sub-resolution strands have been long invoked
as strong candidates for the heating of active region (AR) coronal
loops. However, the frequent occurrence of nanoflares requires the
steady presence of flare-hot plasma in the active region, which
has been difficult to detect so far. We report on the analysis of
multi-filter Hinode/XRT observations of an active region, which may
show the widespread presence of 10 MK plasma.
---------------------------------------------------------
Title: Evidence of Widespread Hot Plasma in a Nonflaring Coronal
Active Region from Hinode/X-Ray Telescope
Authors: Reale, Fabio; Testa, Paola; Klimchuk, James A.; Parenti,
Susanna
2009ApJ...698..756R Altcode: 2009arXiv0904.0878R
Nanoflares, short and intense heat pulses within spatially unresolved
magnetic strands, are now considered a leading candidate to solve
the coronal heating problem. However, the frequent occurrence of
nanoflares requires that flare-hot plasma be present in the corona at
all times. Its detection has proved elusive until now, in part because
the intensities are predicted to be very faint. Here, we report on the
analysis of an active region observed with five filters by Hinode/X-Ray
Telescope (XRT) in 2006 November. We have used the filter ratio method
to derive maps of temperature and emission measure (EM) both in soft and
hard ratios. These maps are approximate in that the plasma is assumed
to be isothermal along each line of sight. Nonetheless, the hardest
available ratio reveals the clear presence of plasma around 10 MK. To
obtain more detailed information about the plasma properties, we have
performed Monte Carlo simulations assuming a variety of nonisothermal
EM distributions along the lines of sight. We find that the observed
filter ratios imply bi-modal distributions consisting of a strong cool
(log T ~ 6.3 - 6.5) component and a weaker (few percent) and hotter (6.6
< log T < 7.2) component. The data are consistent with bi-modal
distributions along all lines of sight, i.e., throughout the active
region. We also find that the isothermal temperature inferred from a
filter ratio depends sensitively on the precise temperature of the cool
component. A slight shift of this component can cause the hot component
to be obscured in a hard ratio measurement. Consequently, temperature
maps made in hard and soft ratios tend to be anti-correlated. We
conclude that this observation supports the presence of widespread
nanoflaring activity in the active region.
---------------------------------------------------------
Title: Observations of Nanoflare Produced Hot ( 10 Mk) Plasma
Authors: Klimchuk, James A.; Reale, F.; Testa, P.; Parenti, S.
2009SPD....40.1214K Altcode:
Indirect observational evidence suggests that some or most of
the corona is heated impulsively on sub-resolution scales by
nanoflares. Theoretical studies of possible heating mechanisms
also support this picture. However, the most direct evidence of
nanoflares---plasma hotter than 5 MK---has been difficult to obtain
because the emission is expected to be very faint. The reason is
two-fold: first, hot plasma cools very rapidly by thermal conduction;
and second, densities are small because chromospheric evaporation
has not had time to fill the corona. Recent observations from several
instruments have now provided strong evidence of hot plasma. We report
here on the detection of 10 MK plasma by the X-Ray Telescope (XRT)
on Hinode. We show that the intensity of the emission is consistent
with nanoflare models, but is extremely difficult to explain with
steady heating.
---------------------------------------------------------
Title: On the ultraviolet signatures of small scale heating in
coronal loops
Authors: Parenti, S.; Young, P. R.
2008A&A...492..857P Altcode: 2010arXiv1009.4112P
Aims: Studying the statistical properties of solar ultraviolet emission
lines could provide information about the nature of small scale coronal
heating. We expand on previous work to investigate these properties. We
study whether the predicted statistical distribution of ion emission
line intensities produced by a specified heating function is affected
by the isoelectronic sequence to which the ion belongs, as well
as the characteristic temperature at which it was formed (as found
previously). Particular emphasis is placed on the strong resonance
lines belonging to the lithium isoelectronic sequence. Predictions
for emission lines observed by existing space-based UV spectrometers
are given. The effects on the statistics of a line when observed with
a wide-band imaging instrument rather than a spectrometer are also
investigated. <BR />Methods: We use a hydrodynamic model to simulate the
UV emission of a loop system heated by nanoflares on small, spatially
unresolved scales. We select lines emitted at similar temperatures
but belonging to different isoelectronic groups: Fe IX and Ne VIII,
Fe XII and Mg X, Fe XVIII, Fe XIX and Fe XXIV. <BR />Results: Our
simulations confirm previous results that almost all lines have an
intensity distribution that follows a power-law, in a similar way
to the heating function. However, only the high temperature lines
best preserve the heating function's power law index (Fe XIX being
the best ion in the case presented here). The Li isoelectronic lines
have different statistical properties with respect to the lines from
other sequences, due to the extended high temperature tail of their
contribution functions. However, this is not the case for Fe XXIV which
may be used as a diagnostic of the coronal heating function. We also
show that the power-law index of the heating function is effectively
preserved when a line is observed by a wide-band imaging instrument
rather than a spectromenter.
---------------------------------------------------------
Title: The redshifted footpoints of coronal loops
Authors: Dammasch, I. E.; Curdt, W.; Dwivedi, B. N.; Parenti, S.
2008AnGeo..26.2955D Altcode:
The physics of coronal loops holds the key to understanding coronal
heating and the flow of mass and energy in the region. However, the
energy source, structure maintenance and mass balance in coronal loops
are not yet fully understood. Observations of blue- and redshifted
emissions have repeatedly been used in the construction of loop
models. But observations and interpretations of line shifts have been
widely debated. Here we present detailed SUMER observations, which
clearly show a steady downflow in both footpoints of coronal loops
observed at transition region (TR) and lower corona temperatures. We
also show and quantify a correlation existing between this Doppler shift
and the spectral radiance. Our results indicate a strong correlation
which holds from the chromosphere to the lower corona. We suggest that
the downflow in the footpoints may be a common phenomenon on all scales,
which could explain, why on a statistical basis bright pixels tend to
be more redshifted. We conclude by presenting interpretation of such
results and their implications in the light of a viable coronal loop
model. The observation of steady downflow in redshifted footpoints
seems to be in conflict with impulsive heating.
---------------------------------------------------------
Title: Fine Thermal Structure of a Flare Observed with Hinode/XRT
Authors: Parenti, S.; Reale, F.; Reeves, K. K.
2008ASPC..397..182P Altcode:
In this work we investigate the fine thermal structure of a flare
observed in November 2006 by Hinode/XRT. For this analysis we adopted
a new technique which optimizes the use of five different filters,
resulting in a good diagnostic of temperature.
---------------------------------------------------------
Title: Heating and Dynamics of Loops and Flares
Authors: Parenti, S.
2008ESPM...12.2.78P Altcode:
Loops may be considered the building blocks of the solar
corona. Understanding their heating and dynamics becomes extremely
important to solve the heating problem in the full corona. <P />The
debate on weather steady or impulsive heating (such as envisioned
by the nanoflares scenario) should be considered as the dominant
heating process in loops, is still lively in the solar community. <P
/>From the observational point of view, key elements to progress on
the understanding of the corona are the correct interpretation of the
observational data together with precise measurements. Limitations are
often present because of the finite resolution of the instruments,
their limited temperature coverage and the fact that we are dealing
with optically thin plasma when observing the corona. In spite of
such limitations, considerable progress has been made in the past
years. Results obtained in the past decades are now strengthened by the
new observations from the Hinode and STEREO missions. <P />This talk
will show and discuss new observational results that address selected
aspects as key elements to understand the physics of loops. These
include: <P />The monolithic vs. multi-thread configurations. Can
we resolve the elemental coronal loop?; <P />Flows and dynamics. New
exciting results from SOHO and Hinode. <P />Loops and active region
thermal structures. Do we have a complete map of them? <P />I will
conclude by briefing introducing the last efforts in the 3D loops
reconstruction: a further essential element to help solving the complex
phenomenon of the loops heating and dynamics.
---------------------------------------------------------
Title: Hinode/XRT Diagnostics of Loop Thermal Structure
Authors: Reale, F.; Parenti, S.; Reeves, K. K.; Weber, M.; Bobra,
M. G.; Barbera, M.; Kano, R.; Narukage, N.; Shimojo, M.; Sakao, T.;
Peres, G.; Golub, L.
2008ASPC..397...50R Altcode:
We investigate possible diagnostics of the thermal structure of coronal
loops from Hinode/XRT observations made with several filters. We
consider the observation of an active region with five filters. We
study various possible combinations of filter data to optimize for
sensitivity to thermal structure and for signal enhancement.
---------------------------------------------------------
Title: Solar prominence properties derived from the UV-EUV SUMER
spectral atlas
Authors: Parenti, S.; Vial, J. -C.; Lemaire, P.
2008AdSpR..41..144P Altcode:
In this paper, we summarize the work done to build a UV-EUV spectral
atlas of a prominence and we introduce some recent scientific
results obtained from these data. For this work we used SOHO/SUMER
data covering the full wavelength range accessible by the instrument
(from about 800 to 1600 Å), when a prominence and the quiet Sun (used
as spectral reference) were observed in October 1998. We present here
only a fraction of the data, which results in the analysis of more
than 600 spectral lines, including some new identifications. Here we
also present the differential emission measure obtained from the data,
both for the quiet Sun and the prominence. The main differences in
characteristics are discussed.
---------------------------------------------------------
Title: Post flare evolution of AR 10923 from Hinode/XRT
Authors: Parenti, Susanna; Reale, Fabio; Reeves, Kathy
2008cosp...37.2353P Altcode: 2008cosp.meet.2353P
The Hinode/XRT high resolution, multi band instrument is a suitable
instrument for the detailed study of the fine structure of the hot
corona. We present the analysis of the morphological and thermal
evolution of AR 10923 loops structures during a post-flare period. The
analysis is performed using the powerful Reale et al. 2007 diagnostic
tool.
---------------------------------------------------------
Title: Methods of Analyzing Temperatures in Post-Flare Loops using
the XRT on Hinode
Authors: Reeves, K. K.; Parenti, S.; Reale, F.; Weber, M. A.
2007AGUFMSH51C..08R Altcode:
The X-Ray Telescope on Hinode has unrivaled temperature coverage, with 9
X-Ray filters in the focal plane. Using 7 different filter combinations,
XRT observed a C8.2 flare on July 10, 2007. We use two different methods
to glean temperature information about the post-flare loop system in
this event. First, we examine the flare loops using the combined filter
ratio method, which is a ratio method that utilizes observations in
multiple filters in order to optimize the signal quality. Secondly, we
calculate temperatures based on a differential emission measure method,
which is a forward fitting method of determining temperatures. The
results of these two methods will be compared.
---------------------------------------------------------
Title: Fine Thermal Structure of a Coronal Active Region
Authors: Reale, Fabio; Parenti, Susanna; Reeves, Kathy K.; Weber,
Mark; Bobra, Monica G.; Barbera, Marco; Kano, Ryouhei; Narukage,
Noriyuki; Shimojo, Masumi; Sakao, Taro; Peres, Giovanni; Golub, Leon
2007Sci...318.1582R Altcode:
The determination of the fine thermal structure of the solar corona is
fundamental to constraining the coronal heating mechanisms. The Hinode
X-ray Telescope collected images of the solar corona in different
passbands, thus providing temperature diagnostics through energy
ratios. By combining different filters to optimize the signal-to-noise
ratio, we observed a coronal active region in five filters, revealing
a highly thermally structured corona: very fine structures in the
core of the region and on a larger scale further away. We observed
continuous thermal distribution along the coronal loops, as well as
entangled structures, and variations of thermal structuring along the
line of sight.
---------------------------------------------------------
Title: Prominence and quiet-Sun plasma parameters derived from FUV
spectral emission
Authors: Parenti, S.; Vial, J. -C.
2007A&A...469.1109P Altcode:
Context: A solar prominence and the quiet-Sun (QS) were observed
with SOHO/SUMER in October 1999. With this dataset we built the
first comprehensive UV spectral atlas in the range 800-1250 Å for a
prominence, thus complementing the existing reference atlases for the
QS. <BR />Aims: This is a detailed study based on the information
in this atlas, with the aim of deriving the plasma parameters in
two distinct regions. The large amount of information available
allows us to establish these parameters with lower uncertainty than
in previous studies, leading to reference values for theoretical
investigations. <BR />Methods: The measured lines' FWHM were used
to derive the distribution of the non-thermal velocities at various
temperatures. The lines intensities were used to derive the electron
densities at temperatures of 7 × 10<SUP>4</SUP> K and the differential
emission measure. <BR />Results: The comparison with the QS shows
lower velocities in the prominence for temperature T with log~T <
5.4. The velocities derived in the highest part of the prominence
show a lower gradient with the temperature. The value obtained for
the electron density indicates a low pressure prominence. We conclude
with a discussion of the energy budget in the prominence. <P />Table
1 is only available in electronic form at http://www.aanda.org
---------------------------------------------------------
Title: EUI, The Ultraviolet Imaging Telescopes Of Solar Orbiter
Authors: Hochedez, J. -F.; Appourchaux, T.; Defise, J. -M.; Harra,
L. K.; Schühle, U.; Auchère, F.; Curdt, W.; Hancock, B.; Kretzschmar,
M.; Lawrence, G.; Leclec'h, J. -C.; Marsch, E.; Mercier, R.; Parenti,
S.; Podladchikova, E.; Ravet, M. -F.; Rochus, P.; Rodriguez, L.;
Rouesnel, F.; Solanki, S.; Teriaca, L.; Van Driel, L.; Vial, J. -C.;
Winter, B.; Zhukov, A.
2007ESASP.641E..33H Altcode:
The scientific objectives of Solar Orbiter rely ubiquitously on EUI,
its suite of solar atmosphere imaging telescopes. In the configuration
discussed here, EUI includes three co-aligned High Resolution Imagers
(HRI) and one Full Sun Imager (FSI). FSI and two HRIs observe in extreme
ultraviolet passbands, dominated by coronal emission. Another HRI is
designed for the hydrogen Lyman α radiation in the far UV, imaging the
Chromosphere and the lower Transition Region. The current EUI design
and some of its development challenges are highlighted. EUI profits from
co-rotation phases, solar proximity and departure from the ecliptic. In
synergy with the other S.O. payload, EUI probes the dynamics of the
solar atmosphere, provides context data for all investigations and helps
to link in-situ and remote-sensing observations. In short, it serves all
four top-level goals of the mission. For these reasons, the EUI suite
is keenly anticipated in the European scientific community and beyond.
---------------------------------------------------------
Title: Magnetic activity and the solar corona: first results from
the Hinode satellite .
Authors: Reale, Fabio; Parenti, Susanna; Reeves, Kathy K.; Weber,
Mark; Bobra, Monica G.; Barbera, Marco; Kano, Ryohei; Narukage,
Noriyuki; Shimojo, Masumi; Sakao, Taro; Peres, Giovanni; Golub, Leon
2007MmSAI..78..591R Altcode:
The structure, dynamics and evolution of the solar corona are governed
by the magnetic field. In spite of significant progresses in our insight
of the physics of the solar corona, several problems are still under
debate, e.g. the role of impulsive events and waves in coronal heating,
and the origin of eruptions, flares and CMEs. The Hinode mission has
started on 22 september 2006 and aims at giving new answers to these
questions. The satellite contains three main instruments, two high
resolution telescopes, one in the optical and one in the X-ray band,
and an EUV imaging spectrometer. On the Italian side, INAF/Osservatorio
Astronomico di Palermo has contributed with the ground-calibration
of the filters of the X-ray telescope. We present some preliminary
mission results, with particular attention to the X-ray telescope data.
---------------------------------------------------------
Title: Modeling the Radiative Signatures of Turbulent Heating in
Coronal Loops
Authors: Parenti, S.; Buchlin, E.; Cargill, P. J.; Galtier, S.; Vial,
J. -C.
2006ApJ...651.1219P Altcode:
The statistical properties of the radiative signature of a coronal loop
subject to turbulent heating obtained from a three-dimensional (3D)
magnetohydrodynamics (MHD) model are studied. The heating and cooling of
a multistrand loop is modeled and synthetic spectra for Fe XII 195.12,
Fe XV 284.163, and Fe XIX 1118.06 Å are calculated, covering a wide
temperature range. The results show that the statistical properties
of the thermal and radiative energies partially reflect those of the
heating function in that power-law distributions are transmitted,
but with very significant changes in the power-law indices. There is
a strong dependence on the subloop geometry. Only high-temperature
radiation (~10<SUP>7</SUP> K) preserves reasonably precise information
on the heating function.
---------------------------------------------------------
Title: Looking for Signature of Coronal Heating in the Radiative
Emission of a Coronal Loop
Authors: Parenti, S.; Buchlin, E.; Cargill, P. J.; Caltier, S.; Vial,
J. -C.
2006ESASP.617E.104P Altcode: 2006soho...17E.104P
No abstract at ADS
---------------------------------------------------------
Title: Solar Hydrogen Lyman Contimuum Observations with Soho/sumer
Authors: Parenti, S.; Vial, J. -C.; Lemaire, P.
2005ESASP.600E..93P Altcode: 2005ESPM...11...93P; 2005dysu.confE..93P
No abstract at ADS
---------------------------------------------------------
Title: Prominence atlas in the SUMER range 800-1250 Å. II. Line
profile properties and ions identifications
Authors: Parenti, S.; Vial, J. -C.; Lemaire, P.
2005A&A...443..679P Altcode:
We present a SOHO/SUMER spectral atlas in the 800-1250 Å range of
a prominence and a Quiet Sun (QS) region observed in 1999. The atlas
is produced for two separate areas of the prominence. The QS spectrum
is used as a reference. This is the first prominence atlas obtained
with high spectral resolution (≈0.044 Å). It provides information
concerning more than 550 line profiles, in terms of position, total
radiance, and FWHM, along with the ion identification. Forty new lines
have been identified with respect to previously published spectra.
---------------------------------------------------------
Title: Solar hydrogen-Lyman continuum observations with SOHO/SUMER
Authors: Parenti, S.; Lemaire, P.; Vial, J. -C.
2005A&A...443..685P Altcode:
In this work we analyze the emission of the H Lyman continuum (HI
LyC) in the Quiet Sun (QS) and a solar prominence, in order to derive
information on the temperature of the emitting plasma. We used the
spectral atlas obtained with SOHO/SUMER detector A in 1999 (Parenti
et al. 2005, A&A, 443, 679). The high spectral resolution of this
instrument allows a good selection of the continuum, free from emission
lines. However, in the HI LyC wavelength domain, the data suffer from
large radiometric uncertainties, which lead us to use detector B as
a reference. We obtained electron temperatures of 8281 K ± 280 K and
7564 K ± 230 K in two separate parts of the prominence.
---------------------------------------------------------
Title: Radiative Signatures of Coronal Loops Submitted to Turbulent
Heating
Authors: Parenti, S.; Buchlin, E.; Galtier, S.; Vial, J. -C.
2005ESASP.592..523P Altcode: 2005soho...16E..97P; 2005ESASP.592E..97P
No abstract at ADS
---------------------------------------------------------
Title: Electron Density and Temperature in Streamer Derived from
the H-LY Emission
Authors: Parenti, S.; Noci, G.
2005ESASP.592..519P Altcode: 2005ESASP.592E..96P; 2005soho...16E..96P
No abstract at ADS
---------------------------------------------------------
Title: Modelling the Radiative Signatures of Turbulent Heating in
Coronal Loops
Authors: Parenti, S.; Buchlin, E.; Galtier, S.; Vial, J. -C.
2004ESASP.575..497P Altcode: 2004soho...15..497P
No abstract at ADS
---------------------------------------------------------
Title: SOHO CDS and SUMER observations of quiescent filaments and
their interpretation
Authors: Del Zanna, G.; Chiuderi Drago, F.; Parenti, S.
2004A&A...420..307D Altcode:
Three quiescent filaments located at different positions on the solar
disk were selected from the SOHO CDS data archive: one of them was also
observed by SUMER in the raster mode. We investigate the filament-corona
transition region (PCTR) emission, to determine whether it is indeed
negligible, as found in one previously-analysed case. The observations
are interpreted on the basis of two different models: an isothermal
(cool) prominence located above the quiet sun transition region (TR)
with a portion of the corona below it, and a model composed of several
cool threads embedded in the hot coronal plasma without any quiet
sun TR below it. The first model indicates that, for all filaments,
the PCTR emission at the top of the filament is indeed negligible, and
that the chromosphere-corona TR emission under the filament is lower
than the average. All filaments have similar column densities, ranging
from ∼2 to 7× 10<SUP>17</SUP> cm<SUP>-2</SUP> according to model A,
and from 5 to 17×10<SUP>17</SUP> cm<SUP>-2</SUP> according to Model
B. It is not possible to determine which model better accounts for the
observations, on the basis of the two prominences observed above and
below the Lyman continuum limit. Model B predicts absorptions that are
generally less consistent with the observations, and produces higher
column densities. The comparison between the line intensities observed
above and below the He I ionization limit provides an estimate of the
relative neutral helium abundance N(He I)/N(H I) in the prominences.
---------------------------------------------------------
Title: Prominence atlas in the SUMER range 800 1250 Å:
I. Observations, data reduction and preliminary results
Authors: Parenti, S.; Vial, J. -C.; Lemaire, P.
2004SoPh..220...61P Altcode:
The aim of this work is to build an EUV-UV spectral catalogue of a
prominence. Here we focus on the preparatory work for the final result
and we give an example of the results obtained. As a first step, we
present the information needed for a full understanding of the results
that will form the final entire catalogue. The data are composed of a
full SUMER spectrum in the range 800-1250 Å of a prominence observed
on 8 October 1999. A quiet-Sun area was also observed in the same
spectral range in order to have a reference spectrum. Beside the
standard corrections, we give details of the estimated stray light
and the wavelength calibration of both datasets. We also present a
short list of lines as an example of the results from the line-fitting
procedure we applied to the data. For each line we give the measured
position, the total intensity and the FWHM in the quiet Sun and at two
different spatial positions in the prominence. With a final atlas of
the prominence it will be possible to investigate several properties
of the feature such as mass motion, differential emission measure,
density, and elemental composition.
---------------------------------------------------------
Title: Solar prominence properties derived from the UV-EUV SUMER
spectral atlas
Authors: Parenti, S.
2004cosp...35.2958P Altcode: 2004cosp.meet.2958P
We present the first results for the properties of solar prominence
obtained using spectral lines from an UV-EUV atlas of prominence. We
built this catalogue using data from the high resolution SUMER
spectrometer on board SOHO. The data are composed by a full spectrum
in the range 800 - 1250 Å of a prominence observed on October 8,
1999. A catalogue of prominence spectra at such spectral and spatial
resolutions is a new item in prominence literature, and much information
on prominences properties ca be derived. The Differential Emission
Measure and other plasma properties are here investigated.
---------------------------------------------------------
Title: Temporal Evolution of a Streamer Complex: Coronal and in Situ
Plasma Parameters
Authors: Bemporad, A.; Poletto, G.; Suess, S. T.; Ko, Y. K.; Parenti,
S.; Riley, P.; Romoli, M.; Zurbuchen, T. Z.
2003ApJ...593.1146B Altcode:
We report on observations acquired by the Ultraviolet Coronagraph
Spectrometer (UVCS) aboard the Solar and Heliospheric Observatory
(SOHO), from 2000 June 10 to June 17 at the time of a SOHO-Sun-Ulysses
quadrature. UVCS took data at 1.6 and 1.9 R<SUB>solar</SUB> with a slit
normal to the solar radius and centered along the radial to Ulysses. A
streamer complex was sampled by UVCS throughout the quadrature
campaign, giving us the opportunity to derive plasma parameters
in different streamers and to compare them with plasma properties
measured in situ. Large Angle Spectroscopic Coronagraph images above 2
R<SUB>solar</SUB> helped us understand the temporal evolution of the
streamer complex. We derive densities, temperatures, and elemental
abundances in two streamers, which have different temperatures and
element abundances. In spite of these differences, both structures
have the same first ionization potential (FIP) bias. The Fe/O ratio,
which may be considered a proxy for the FIP effect, was measured in
situ by the Solar Wind Ion Composition Spectrometer aboard the Ulysses
spacecraft. Values of Fe/O measured in the corona at the sites where
in situ plasma originated agree with in situ Fe/O values.
---------------------------------------------------------
Title: SOHO-Ulysses Spring 2000 Quadrature: Coronal Diagnostic
Spectrometer and SUMER Results
Authors: Parenti, S.; Landi, E.; Bromage, B. J. I.
2003ApJ...590..519P Altcode:
We present results from SOHO/CDS and SOHO/SUMER coordinated observations
of coronal streamers made during the spring 2000 quadrature of SOHO,
the Sun, and Ulysses. These observations form part of the JOP 112,
which is primarily aimed at investigating the composition of the
regions of the corona and the solar wind observed by both SOHO and
Ulysses. SUMER and CDS observed the low corona from the limb up
to about 1.3 R<SUB>solar</SUB> from the Sun center. The physical
parameters of the plasma, such as electron density, temperature,
emission measure, and composition, are measured along the radial
direction, toward Ulysses. The variation in these parameters over the
6 day series of observations was examined, and no significant change
was seen. The dependence of these parameters on the solar latitude was
also investigated. The results indicate that the observed streamers
are homogeneous, of coronal composition, and nearly in hydrostatic
equilibrium. The structures remained almost stable during the whole
period of the observations.
---------------------------------------------------------
Title: Properties of the base of streamers from UV and EUV
observations
Authors: Parenti, S.; Landi, E.; Bromage, B. J. I.
2003MmSAI..74..717P Altcode:
In this paper we investigate the physical parameters of a streamer
observed during the Spring 2000 quadrature of SOHO, the Sun and
Ulysses. The analysis was carried out using SOHO/CDS and SOHO/SUMER
coordinated observations of the low corona. We analysed six days
of observations of the same region, deriving electron temperature,
density, emission measure and composition. We found full agreement
in the results from the two instruments. We conclude that we were
observing an omogeneus streamer, with coronal composition and not
completely isothermal.
---------------------------------------------------------
Title: The "careers in solar physics" session of the SPM10 meeting
Authors: Aulanier, G.; Parenti, S.; Krijger, J. M.
2002ESASP.506..981A Altcode: 2002ESPM...10..981A; 2002svco.conf..981A
During the SPM10 meeting held in Prague (Czech Republic) on September
9-14, 2002, a half-day 'young session' was organized on the topic
of careers in solar physics. Several young researchers and senior
scientists were invited to give oral contributions on the current
advantages and difficulties attached to the current system for
post-doctoral contracts. A scientist from USA also presented the
American system for contractors, and an ESA representative presented
the official position of ESA regarding funding researchers. From
the talks as well as from the long open discussion which followed,
it was widely agreed that several typical rules for EU post-doc
contracts (their short duration, their mandatory mobility, their
age limit and their administrative and financial difficulties) not
only lead to serious problems in the private life of postdocs, but
essentially can have serious drawbacks on the follow-up of long-term
scientific developments, and could quickly result in a dramatic loss
of expertise, from the scale of individual institutes to the European
scientific community at large. Many participants and most of the young
researchers naturally agreed that new longer-term, renewable and stable
contracts are necessary. In order to create such types of contracts,
several fund raising initiative achieveable by the scientific community
were discussed. The development of better public outreach initiatives
on the European scale was a possibility which federated most of the
participants. The resulting conclusion on this session were transmitted
to the new board of the Solar Physics Section of the EAS/SPS.
---------------------------------------------------------
Title: The European solar physics community: outcome from a
questionnaire
Authors: Parenti, Susanna
2002ESASP.506..985P Altcode: 2002svco.conf..985P; 2002ESPM...10..985P
At the SPM10 meeting held in Prague, for the first time was organized a
"young section" which was dedicated to "the career in Solar Physics"
(Aulanier, this issue). Prior to the meeting a questionnaire was
distributed to the community with the aim to build statistic on the
career. The informations collected in this way relate to personal and
professional aspects of the career, how much the countries' policy and
the working environment can affect it. Moreover, particular attention
was given to the PhD and post-doctorate (post-doc) conditions. From the
statistics it comes clear that the European Solar Physics is having
a difficult period. Besides the main problems, we found the lack of
an integrated European community, the lack of permanent positions,
the low salary and the lost of popularity among students. Several
ideas were proposed to improve the situation.
---------------------------------------------------------
Title: A SUMER spectral atlas for prominences
Authors: Parenti, Susanna; Vial, J. -C.; Lemaire, P.
2002ESASP.508..327P Altcode: 2002soho...11..327P
We present preliminary results of a study aimed at building a SUMER
atlas for prominences. Using the atlas as reference, further studies
can be addressed at deriving prominence properties, such as DEM
distribution and anomalies in element abundances. Moreover, a comparison
with previous atlas (e.g. Curdt et al., 2001) of other solar regions
can be made. An extended prominence was observed with SUMER in the
South-West solar limb in October 1999. A full spectrum was obtained
in the waveband 790 - 1600 Å. After dealing with off-limb scattered
light, the data are processed using multi-Gaussian fitting in order
to derive the spectral properties of the observed structure. These
properties are then also compared with those of the Quiet Sun area
observed in the same wavelength range.
---------------------------------------------------------
Title: SOHO/CDS and SUMER coordinated observations of coronal streamer
Authors: Parenti, Susanna; Landi, Enrico; Bromage, B. J. I.
2002ESASP.508..399P Altcode: 2002soho...11..399P
In June 2000 the SOHO and Ulysses satellites reached the quadrature
configuration with respect to the Sun. On this occasion the JOP 112
was run, with the aim of studying the coronal and solar wind physical
parameters, with particular attention to the element composition. In
this paper we present preliminary results from SOHO/SUMER and CDS/NIS
data. The two instruments were pointed off-limb and observed the
lower solar corona in the Ulysses direction (-58.2 deg in the S-E
quadrant). During the period of observations (12-17 June) the observed
corona was filled with streamers. From each instrument the electron
density, temperature and element composition of the studied areas have
been derived. A comparison of the results from the two instruments is
then presented.
---------------------------------------------------------
Title: An erupting macrospicule. Characteristics derived from SOHO-CDS
spectroscopic observations
Authors: Parenti, S.; Bromage, B. J. I.; Bromage, G. E.
2002A&A...384..303P Altcode:
We report results from the analysis of a sequence of SOHO/CDS
observations obtained off-limb in the south polar coronal hole on
6 March 1998. Three successive data sets were obtained with the
Normal Incidence Spectrometer (NIS), the first of which showed a
jet-like feature visible in the chromospheric and low transition
region lines. The morphological characteristics of this feature
suggested it was a macrospicule. The two remaining observations of
the same region indicated a quiet coronal hole with a density of
10<SUP>8</SUP> cm<SUP>-3</SUP> and a temperature rising from 0.95
x 10<SUP>6</SUP> K near the limb to 1.2 x 10<SUP>6</SUP> K at about
4.7 x 10<SUP>4</SUP> km above the limb. These data were averaged and
used as “background” for the macrospicule observation. The resulting
subtracted spectra showed more details of the feature. In particular,
a cloud of plasma was detected at about 3 x 10<SUP>4</SUP> km above
the limb. The macrospicule was found to have a density of the order
of 10<SUP>10</SUP> cm<SUP>-3</SUP> and a temperature of about 2-3
x 10<SUP>5</SUP> K. The initial outflow velocity near the limb was
over 80 km s<SUP>-1</SUP>. This decreased to a terminal value of 26
km s<SUP>-1</SUP> above about 6 x 10<SUP>4</SUP> km.
---------------------------------------------------------
Title: Preliminary results from coordinated SOHO-Ulysses observations
Authors: Parenti, S.; Poletto, G.; Bromage, B. J. I.; Suess, S. T.;
Raymond, J. C.; Noci, G.; Bromage, G. E.
2001AIPC..598...83P Altcode: 2001sgc..conf...83P
SOHO-Ulysses quadratures occur at times when the SOHO-Sun-Ulysses angle
is 90° and offer a unique possibility to compare properties of plasma
parcels observed in the low corona with properties of the same parcels
measured, in due time, in situ. The June 2000 quadrature occurred
at a time Ulysses was at 3.35 AU and at a latitude of 58.2 degrees
in the south-east quadrant. Here we focus on the UVCS observations
made on June 11, 12, 13, 16. UVCS data were acquired at heliocentric
altitudes ranging from 1.6 to 2.2 solar radii, using different grating
positions, in order to get a wide wavelength range. The radial direction
to Ulysses, throughout the 4 days of observation, traversed a region
where high latitude streamers were present. Analysis of the spectra
taken by UVCS along this direction shows a variation of the element
abundances in the streamers over our observing interval: however,
because the radial to Ulysses crosses through different parts of
streamers in different days, the variation could be ascribed either
to a temporal or to a spatial effect. The oxygen abundance, however,
seems to increase at the edge of streamers, as indicated by previous
analyses. This suggests the variation may be a function of position
within the streamer, rather than a temporal effect. Physical conditions
in streamers, as derived from UVCS observations, are also discussed. .
---------------------------------------------------------
Title: Coronal and solar wind elemental abundances
Authors: Raymond, J. C.; Mazur, J. E.; Allegrini, F.; Antonucci, E.;
Del Zanna, G.; Giordano, S.; Ho, G.; Ko, Y. -K.; Landi, E.; Lazarus,
A.; Parenti, S.; Poletto, G.; Reinard, A.; Rodriguez-Pacheco, J.;
Teriaca, L.; Wurz, P.; Zangrilli, L.
2001AIPC..598...49R Altcode: 2001sgc..conf...49R
Coronal elemental abundances, as compared with abundances in the solar
wind and solar energetic particles, provide the means for connecting
solar wind gas with its coronal source. Comparison of coronal abundances
with photospheric values shows fractionation with the ionization
potential of the atom, providing important, though not yet fully
understood, information about the exchange of material between corona
and chromosphere. Fractionation due to gravitational settling provides
clues about flows within the corona. In this paper, we discuss the
uncertainties of abundance determinations with spectroscopic techniques
and in situ measurements, we survey the ranges of abundance variations
in both the corona and solar wind, and we discuss the progress in
correlating solar wind features with their coronal sources. .
---------------------------------------------------------
Title: Properties of Different Coronal Stremers
Authors: Parenti, S.; Bromage, B. J. I.; Poletto, G.; Noci, G.;
Reymond, J. C.; Bromage, G. E.
2001IAUS..203..413P Altcode:
Element abundance in equatorial and mid-latitude streamers have been
derived from data taken by SOHO/CDS and UVCS experiments. Observations
were made at 1.1, 1.5,1.6 R<SUB>odot</SUB>, to allow us to check
a possible variation of elemental composition with altitude. Part
of the CDS data were taken at the border of the south Corona Hole,
so that the variation of coronal composition at the streamer edge is
investigated. UVCS spectra have been acquired using three different
grating positions to cover lines from low and high First Ionization
Potential. Absolute abundance of Oxygen and Iron have been determined
via the evaluation of the radiat ive and collisional components
of the H-Lyman β and O VI (1032 Å) lines and of th e intensities
of lines from Fe X-XIII-XV-XVIII. Abundance of Fe, Si, Al, Mg were
estimated using the Differential Emission Measure technique. This
method gives us information also on the plasma electron temperature
(T<SUB>e</SUB>), which is compared with temperatures estimates from line
ratio technique. The variability of (T<SUB>e</SUB>) and of abundances
in the observed streamers are discussed and compared with estimates
from the literature.
---------------------------------------------------------
Title: Element abundances in streamers from SOHO/UVCS CDS observations
Authors: Parenti, S.; Poletto, G.; Bromage, B. J. I.; Raymond, J. C.;
Noci, G.
2001MmSAI..72..604P Altcode:
The variation of the element abundances in coronal streamers with
solar distance and latitude has been studied. The data were acquired
in an equatorial and mid-latitude streamer by SOHO/UVCS and CDS,
during a coordinated observing campaign held on March, 8 1998. CDS
data refer to 1.1 solar radii, UVCS data to 1.6 solar radii. A
further mid-latitude streamer was observed by UVCS at 1.6 solar
radii, on May 24 of the same year. Element abundances, relative to
photospheric iron, were derived from CDS data using the Differential
Emission Measure (DEM) technique. Absolute element abundances were
derived from UVCS data using a) the O VI doublet lines for oxygen,
b) the line ratio between Fe lines and Lyman-beta for iron and, c)
the DEM technique for the other elements. Our results show a depletion
of the abundances from their photospheric values in the high corona,
while almost photospheric values of the abundances relative to iron
have been found in the low corona. Spectra do not show any clear
indication for a latitude dependence of elemental abundances.
---------------------------------------------------------
Title: EUV Macrospicule in an Off-Limb Observation of the Solar
South Coronal Hole (CD-ROM Directory: contribs/parenti)
Authors: Parenti, S.; Bromage, G. E.; Del Zanna, G.; Bromage, B. J. I.
2001ASPC..223..715P Altcode: 2001csss...11..715P
No abstract at ADS
---------------------------------------------------------
Title: Characteristics of solar coronal streamers. Element
abundance, temperature and density from coordinated CDS and UVCS
SOHO observations
Authors: Parenti, S.; Bromage, B. J. I.; Poletto, G.; Noci, G.;
Raymond, J. C.; Bromage, G. E.
2000A&A...363..800P Altcode:
This paper presents the results from coordinated observations of
streamers acquired by the SOHO Coronal Diagnostic Spectrometer (CDS)
and UltraViolet Coronograph Spectrometer (UVCS) experiments. Data
from different altitudes within the solar corona were taken, with
the purpose of determining their physical parameters - densities,
electron temperatures and element abundances - and their changes
over the altitude range between 1.02 and 1.6 R_sun. Further UVCS
streamer data, taken about two months later are used for comparison
with the behaviour seen in two different streamers. Whenever possible,
alternative methods have been adopted to determine the same physical
parameter, as a cross check. In particular, the DEM technique has
been applied to UVCS data, in order to compare abundance values
derived in this way, with those obtained using the method of Raymond
et al. (\cite{ray97}). We conclude that abundances in the low corona
covered by CDS data do not show evidence for abundance variation, with
respect to photospheric values, while, at UVCS altitudes, a depletion
of all element abundances is clearly evident. No clear evidence of
a FIP effect in streamers was found; we get contrasting results from
the only two high FIP elements present in our spectra.
---------------------------------------------------------
Title: A SOHO/CDS Observation of a Macrospicule in the South
Coronal Hole
Authors: Parenti, S.; Del Zanna, G.; Bromage, B. J. I.
1999ESASP.448..623P Altcode: 1999mfsp.conf..623P; 1999ESPM....9..623P
No abstract at ADS
---------------------------------------------------------
Title: Physical Parameters in Streamer From CDS and UVCS Observations
Authors: Parenti, S.; Poletto, G.; Raymond, J.; Bromage, B. J. I.
1999ESASP.446..531P Altcode: 1999soho....8..531P
UVCS and CDS observations of a streamer in the southern hemisphere,
at a latitude of 40 Degrees, have been acquired on March 8, 1998. UVCS
data have been taken at an heliocentric altitude of 1.6 solar radii and
cover the spectral range from 950 to 1250 Angstrom; CDS data have been
taken at an altitude of 1.1 solar radii and cover the range from 308 to
381, and 513 to 633, Angstrom. These data have been used to determine
the physical conditions of a streamer structure: in particular, we give
an estimate of the electron temperature, electron density and element
abundance in the structure. The electron temperature has been evaluated
from lines of different ions from the same elements, crude values of
densities have been derived from an analysis of the OVI doublet lines
at 1032 and 1037 Angstrom and element abundances have been estimated
both from a DEM (Differential Emission Measure) analysis and from other
techniques. Because UVCS spectra have been taken at different times,
during the day, we have been looking also at temporal variations in
the physical parameters of the streamer. Changes across the streamer
have been analyzed as well. Coordinated CDS and UVCS observations
allow us also to compare results from the two experiments and look for
variations, with solar distance, of the streamer physical parameters.
---------------------------------------------------------
Title: Magnetic Flux Tubes at 3 Au?
Authors: Parenti, S.; Velli, M.; Poletto, G.; Suess, S. T.; McComas,
D. J.
1997SoPh..174..329P Altcode:
We present an analysis of plasma and magnetic field data acquired by
the Ulysses spacecraft on May 1994. Our study is motivated by the
result of Poletto et al. (1996) who found some evidence for a peak
in the power spectrum of magnetic pressure at a frequency ν ≈
2 × 10−<SUP>5</SUP> Hz, during that period. A re-evaluation of
the plasma pressure power spectrum, on the basis of better data than
used in the previous work, gives only marginal evidence for a peak at
that frequency. If both spectra had excess power in the same spectral
range, one might hypothesize that the Pressure Balanced Structures
(PBS) detected in the data trace periodically distributed coronal
structures which maintain their identity up to large distances. A
careful data analysis, however, shows that this interpretation is
hardly tenable. Hence, we consider the alternative hypotheses that
the observed PBS are either a bundle of magnetic flux tubes, with no
characteristic periodicity, in pressure equilibrium with the ambient,
or the manifestation, at large distances, of waves generated close to
the Sun. To prove the latter case, we made a test simulation of the
evolution with heliocentric distance of an ensemble of Alfvén and
slow mode waves, generated close to the Sun, and show that structures
similar to those we analyzed may form in the interplanetary medium. Our
simulations also seem to show that together with PBS, magnetic holes,
frequently observed in the Ulysses data, could also originate from the
nonlinear evolution of large amplitude slow waves in quasi-perpendicular
propagation. We conclude that the observed PBS most likely arise via
an in situ generation mechanism, rather than being remnants of solar
structures.
---------------------------------------------------------
Title: Searching for coronal plumes in ULYSSES observations of the
far solar wind.
Authors: Poletto, G.; Parenti, S.; Noci, G.; Livi, S.; Suess, S. T.;
Balogh, A.; McComas, D. J.
1996A&A...316..374P Altcode:
In the past, from the analysis of data acquired by the Helios
spacecrafts within distances <=1AU, some evidence has been found of
the presence of coronal plumes in the solar wind. Ulysses observations
offer a unique opportunity to search for plume remnants in the
polar wind at larger distances. Pressure balanced structures (PBS),
which might possibly be a signature of those features, have in fact
been recently identified in its data. On the basis of previous work,
which detected significant peaks (possibly related to plumes) in power
spectra of solar wind parameters, we present here the results from
a similar research. However, our analysis does not confirm previous
findings, because power spectra bear no evidence of significant
periodicities. This result allows for different interpretations,
but does not rule out the presence of a typical periodicity in the
data. By developing a simple 2-D model for structures traversed by
Ulysses, we show how easily, even if they were regularly distributed,
the original periodicity may become hardly identifiable in power
spectra analyses. We conclude that this is not a viable technique for
tracing plumes in the solar wind and we suggest alternative means for
an unambiguous identification of these features.
---------------------------------------------------------
Title: Search for fine scale structures in high latitude solar wind
Authors: Livi, S.; Parenti, S.; Poletto, G.
1995sowi.conf...93L Altcode:
About 25 years ago, E. Parker suggested that, as a consequence of the
inhomogeneous structure of the corona, the solar wind might consist
of adjacent structures with different physical conditions. Since that
suggestion was made, the solar wind plasma characteristics have been
measured in situ through many experiments, but little has been done
to check whether the solar wind shows any evidence for fine scale
structures, and, in the affirmative, how far from the Sun these
structures persist. A previous work on this subject, by Thieme,
Marsch and Schwenn (1990), based on Helios data, lead these authors
to claim that the solar wind, between 0.3 and 1 AU, is inhomogeneous
on a scale consistent with the hypothesis that the plume-interplume
plasmas, at those distances, still retain their identity. In this work
we present preliminary results from an investigation of the solar wind
fine structure from Ulysses high latitude observations. To this end,
we have analyzed data over several months, during 1994, at times well
after Ulysses's last encounter with the Heliospheric Current Sheet,
when the spacecraft was at latitudes above 50 degrees. These data refer
to high speed wind coming from southern polar coronal holes and are
best suited for plume-interplume identification. We have performed a
power spectra analysis of typical plasma parameters, to test whether
the wind plasma consist of two distinct plasma populations. We also
examined data to check whether there is any evidence for an horizontal
pressure balance over the hypothesized distinct structures. Our results
are discussed and compared with previous findings.
