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Author name code: domingo
ADS astronomy entries on 2022-09-14
author:"Domingo, Vicente"
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Title: The Polarimetric and Helioseismic Imager on Solar Orbiter
Authors: Solanki, S. K.; del Toro Iniesta, J. C.; Woch, J.; Gandorfer,
A.; Hirzberger, J.; Alvarez-Herrero, A.; Appourchaux, T.; Martínez
Pillet, V.; Pérez-Grande, I.; Sanchis Kilders, E.; Schmidt, W.;
Gómez Cama, J. M.; Michalik, H.; Deutsch, W.; Fernandez-Rico, G.;
Grauf, B.; Gizon, L.; Heerlein, K.; Kolleck, M.; Lagg, A.; Meller, R.;
Müller, R.; Schühle, U.; Staub, J.; Albert, K.; Alvarez Copano, M.;
Beckmann, U.; Bischoff, J.; Busse, D.; Enge, R.; Frahm, S.; Germerott,
D.; Guerrero, L.; Löptien, B.; Meierdierks, T.; Oberdorfer, D.;
Papagiannaki, I.; Ramanath, S.; Schou, J.; Werner, S.; Yang, D.;
Zerr, A.; Bergmann, M.; Bochmann, J.; Heinrichs, J.; Meyer, S.;
Monecke, M.; Müller, M. -F.; Sperling, M.; Álvarez García, D.;
Aparicio, B.; Balaguer Jiménez, M.; Bellot Rubio, L. R.; Cobos
Carracosa, J. P.; Girela, F.; Hernández Expósito, D.; Herranz, M.;
Labrousse, P.; López Jiménez, A.; Orozco Suárez, D.; Ramos, J. L.;
Barandiarán, J.; Bastide, L.; Campuzano, C.; Cebollero, M.; Dávila,
B.; Fernández-Medina, A.; García Parejo, P.; Garranzo-García, D.;
Laguna, H.; Martín, J. A.; Navarro, R.; Núñez Peral, A.; Royo, M.;
Sánchez, A.; Silva-López, M.; Vera, I.; Villanueva, J.; Fourmond,
J. -J.; de Galarreta, C. Ruiz; Bouzit, M.; Hervier, V.; Le Clec'h,
J. C.; Szwec, N.; Chaigneau, M.; Buttice, V.; Dominguez-Tagle, C.;
Philippon, A.; Boumier, P.; Le Cocguen, R.; Baranjuk, G.; Bell,
A.; Berkefeld, Th.; Baumgartner, J.; Heidecke, F.; Maue, T.; Nakai,
E.; Scheiffelen, T.; Sigwarth, M.; Soltau, D.; Volkmer, R.; Blanco
Rodríguez, J.; Domingo, V.; Ferreres Sabater, A.; Gasent Blesa,
J. L.; Rodríguez Martínez, P.; Osorno Caudel, D.; Bosch, J.; Casas,
A.; Carmona, M.; Herms, A.; Roma, D.; Alonso, G.; Gómez-Sanjuan, A.;
Piqueras, J.; Torralbo, I.; Fiethe, B.; Guan, Y.; Lange, T.; Michel,
H.; Bonet, J. A.; Fahmy, S.; Müller, D.; Zouganelis, I.
2020A&A...642A..11S Altcode: 2019arXiv190311061S
<BR /> Aims: This paper describes the Polarimetric and Helioseismic
Imager on the Solar Orbiter mission (SO/PHI), the first magnetograph and
helioseismology instrument to observe the Sun from outside the Sun-Earth
line. It is the key instrument meant to address the top-level science
question: How does the solar dynamo work and drive connections between
the Sun and the heliosphere? SO/PHI will also play an important role
in answering the other top-level science questions of Solar Orbiter,
while hosting the potential of a rich return in further science. <BR
/> Methods: SO/PHI measures the Zeeman effect and the Doppler shift
in the Fe I 617.3 nm spectral line. To this end, the instrument
carries out narrow-band imaging spectro-polarimetry using a tunable
LiNbO<SUB>3</SUB> Fabry-Perot etalon, while the polarisation modulation
is done with liquid crystal variable retarders. The line and the nearby
continuum are sampled at six wavelength points and the data are recorded
by a 2k × 2k CMOS detector. To save valuable telemetry, the raw data
are reduced on board, including being inverted under the assumption of
a Milne-Eddington atmosphere, although simpler reduction methods are
also available on board. SO/PHI is composed of two telescopes; one,
the Full Disc Telescope, covers the full solar disc at all phases of
the orbit, while the other, the High Resolution Telescope, can resolve
structures as small as 200 km on the Sun at closest perihelion. The high
heat load generated through proximity to the Sun is greatly reduced by
the multilayer-coated entrance windows to the two telescopes that allow
less than 4% of the total sunlight to enter the instrument, most of
it in a narrow wavelength band around the chosen spectral line. <BR />
Results: SO/PHI was designed and built by a consortium having partners
in Germany, Spain, and France. The flight model was delivered to
Airbus Defence and Space, Stevenage, and successfully integrated into
the Solar Orbiter spacecraft. A number of innovations were introduced
compared with earlier space-based spectropolarimeters, thus allowing
SO/PHI to fit into the tight mass, volume, power and telemetry budgets
provided by the Solar Orbiter spacecraft and to meet the (e.g. thermal)
challenges posed by the mission's highly elliptical orbit.
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Title: Small magnetic structures near the polar regions of the Sun
Authors: Cabello, I.; Blanco Rodríguez, J.; Balmaceda, L.; Domingo, V.
2017IAUS..327...40C Altcode:
The study of the small magnetic structures of the solar photosphere
is of great relevance because of their association with concentrations
of magnetic field and their possible contribution to the variations of
the Total Solar Irradiance. These structures are known to appear close
to active regions and ubiquitously in the quiet Sun areas. Numerous
studies about their distribution across all over the solar surface
have been done with high-resolution instrumentation. However, since the
observations have always been carried out from the ecliptic plane, their
distribution near the polar regions is not well known. Future missions,
like Solar Orbiter, will certainly provide valuable information on
these yet unexplored regions. In this work, and in preparation for
that moment, we select favorable periods for the observation of the
polar regions of the Sun, and study the fraction of covered surface
by small magnetic structures and its variation with the solar activity.
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Title: Detección y análisis de pequeñas estructuras magnéticas
en las regiones próximas a los polos solares
Authors: Cabello, I.; Blanco Rodríguez, J.; Balmaceda, L.; Domingo, V.
2017BAAA...59..154C Altcode:
The solar magnetic field plays a fundamental role in the overall
behaviour of the Sun. In the solar photosphere, the magnetic field
is evidenced with a wide range of structures with different sizes,
shapes and intensities. Bright Points (BPs) are the smallest of these
manifestations discernible with the current instruments, and their
presence is observable all over the solar disk, on both active and
quiet regions. However, due to difficulties in observing polar areas,
the presence of BPs in these regions is poorly known so far. The Solar
Orbiter mission will be launched in 2018 and will observe the Sun up
to 30º outside the ecliptic, allowing the analysis of BPs appearance
in areas close to the solar poles. A preliminar study can be done
considering the inclination of the ecliptic plane relative to the
solar axis, so that these regions can be observed at certain times
in the year. In this work, G-band images have been used to detect and
analyse BPs located in areas close to the solar poles.
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Title: Multi-wavelength observations of vortex-like flows in the
photosphere using ground-based and space-borne telescopes
Authors: Palacios, J.; Vargas Domínguez, S.; Balmaceda, L. A.;
Cabello, I.; Domingo, V.
2017arXiv170400660P Altcode:
In this work we follow a series of papers on high-resolution
observations of small-scale structures in the solar atmosphere
\citep[][Cabello et al., in prep]{Balmaceda2009, Balmaceda2010,
Vargas2011, Palacios2012, Domingo2012, Vargas2015}, combining several
multi-wavelength data series. These were acquired by both ground-based
(SST) and space-borne (Hinode) instruments during the joint campaign of
the Hinode Operation Program 14, in September 2007. Diffraction-limited
SST data were taken in the G-band and G-cont, and were restored by
the MFBD technique. Hinode instruments, on the other hand, provided
multispectral data from SOT-FG in the CN band, and Mg~{\sc I} and
Ca {\sc II}~lines, as well as from SOT-SP in the Fe~{\sc I} line. In
this series of works we have thoroughly studied vortex flows and their
statistical occurrences, horizontal velocity fields by means of Local
Correlation Tracking (LCT), divergence and vorticity. Taking advantage
of the high-cadence and high spatial resolution data, we have also
studied bright point statistics and magnetic field intensification,
highlighting the importance of the smallest-scale magnetic element
observations.
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Title: Multi-wavelength Observations of Photospheric Vortex Flows
in the Photosphere Using Ground-based and Space-borne Telescopes
Authors: Palacios, J.; Vargas Domínguez, S.; Balmaceda, L. A.;
Cabello, I.; Domingo, V.
2016ASPC..504..139P Altcode:
In this work we follow a series of papers on high-resolution
observations of small-scale structures in the solar atmosphere
(Balmaceda et al. 2009, 2010; Vargas Domínguez et al. 2011; Palacios et
al. 2012; Domingo et al. 2012; Vargas Domínguez et al. 2015, Cabello et
al., in prep), combining several multi-wavelength data series. These
were acquired by both ground-based (SST) and space-borne (Hinode)
instruments during the joint campaign of the Hinode Operation Program
14, in September 2007. Diffraction-limited SST data were taken in the
G-band and G-cont, and were restored by the MFBD technique. Hinode
instruments, on the other hand, provided multispectral data from SOT-FG
in the CN band, and Mg I and Ca II lines, as well as from SOT-SP in
the Fe I line. In this series of works we have thoroughly studied
vortex flows and their statistical occurrences, horizontal velocity
fields by means of Local Correlation Tracking (LCT), divergence and
vorticity. Taking advantage of the high-cadence and high spatial
resolution data, we have also studied bright point statistics and
magnetic field intensification, highlighting the importance of the
smallest-scale magnetic element observations.
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Title: Influence of a plasma swirl motion on fine magnetic
concentrations in the solar photosphere
Authors: Palacios, Judith; Balmaceda, Laura; Cabello, Iballa; Domingo,
Vicente
2016Tecci..11....1P Altcode:
High-resolution observations from ground-based (Solar Swedish Telescope)
and space-borne (Hinode) solar telescopes acquired data with various
filters, obtaining images of a quiet Sun region populated with
small-scale magnetic elements. The region is also characterized by the
presence of photospheric swirl convective plasma structures. This work
abridges the results of different analyses applied over time series of
images to follow the evolution of magnetic features aiming to establish
the influence of the plasma vortices on their motions.
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Title: Evolution of Small-Scale Magnetic Elements in the Vicinity
of Granular-Sized Swirl Convective Motions
Authors: Vargas Domínguez, S.; Palacios, J.; Balmaceda, L.; Cabello,
I.; Domingo, V.
2015SoPh..290..301V Altcode: 2014SoPh..tmp..187V; 2014arXiv1405.2380V
Advances in solar instrumentation have led to widespread use of time
series to study the dynamics of solar features, especially at small
spatial scales and at very fast cadences. Physical processes at such
scales are important as building blocks for many other processes
occurring from the lower to the upper layers of the solar atmosphere
and beyond, ultimately for understanding the larger picture of solar
activity. Ground-based (Swedish Solar Telescope) and space-borne
(Hinode) high-resolution solar data are analyzed in a quiet-Sun region
that displays negative-polarity small-scale magnetic concentrations
and a cluster of bright points observed in G-band. The region is
characterized by two granular-sized convective vortex-type plasma
motions, one of which appears to be affecting the dynamics of magnetic
features and bright points in its vicinity and is therefore the main
target of our investigations. We followed the evolution of the bright
points, intensity variations at different atmospheric height, and
the magnetic evolution for a set of interesting selected regions. We
describe the evolution of the photospheric plasma motions in the region
near the convective vortex and some plausible cases for convective
collapse detected in Stokes profiles.
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Title: Magnetic evolution of faculae observed with IMaX
Authors: Blanco, J.; Palacios, J.; Cabello, I.; Domingo, V.;
Sunrise Team
2013hsa7.conf..803B Altcode:
The SUNRISE mission, consisting of a one metre diameter telescope on
board a stratospheric balloon, was launched on June 2009 on route over
the artic circle. At approximately 36 km height, the balloon flight
allowed to observe with almost no atmospheric influence yielding
very good quality data as well as observations in ultraviolet
spectral lines (by means of the SUFI instrument). The mission's
artic summer-circumpolar flight path provided continuous solar
observations, without day-night cycles, during the almost 5 days of
the mission. IMaX/SUNRISE instrument --developed by a consortium of
Spanish institutions-- is a spectropolarimeter based in the use of a
Fabry-Pérot etalon and liquid crystals for spectral and polarimetric
analysis, respectively. It obtained full-Stokes vector maps at the
selected wavelength of Fe I 5250.2 Å with a temporal cadence of
around 30 seconds and a spatial resolution of approximately 0.15--0.18
arcsec. In this poster, we present a temporal series of a group of limb
faculae comprising approximately 21 minutes. Thanks to the data quality,
as well as the full-Stokes maps and fast temporal cadence, small-scale
magnetic cancellations and emergences can be observed around and at
the faculae positions. We focused on a small area of the instrument
field of view where the cancellation magnetogram shows high magnetic
polarity changes. What we observe are confronted patches of opposite
polarities from the longitudinal magnetic field, being cancelled
and reappearing, while the transversal field signal present changes
also accordingly. This reflects as well in the continuum intensity
images where facular brightenings are seen enhancing and decreasing
in consonance with the transversal field evolution. Studies of this
cancellation phenomena and evolution of the facular structures as
magnetic tubes are being performed for more thorough analyses.
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Title: Study of small magnetic structures in the solar photosphere
Authors: Cabello, I.; Domingo, V.; Bonet, J. A.; Blanco Rodríguez,
J.; Balmaceda, L. A.
2013hsa7.conf..805C Altcode:
The study of small scale magnetic structures in the solar photosphere
is of great relevance for the understanding of the global behaviour of
the Sun. Because of the small spatial and temporal scales involved, the
use of high resolution images and fast cadence is fundamental for their
study. In order to obtain such images, sophisticated computational
techniques that compensate for the atmospheric degradation and
telescope aberration have been developed, improving in this way the
spatial resolution. In this work, we use G-band images obtained with
the 1 m-Swedish Solar Telescope located at La Palma (Canary Islands,
Spain). The images have been restored with MOMFBD (Multi-Object
Multi-Frame Blind Deconvolution), a technique that combines multiple
images acquired in a short time interval. The resulting images have
a resolution close to the diffraction limit of the telescope (0.1
arcsec) allowing the study of very small bright structures present
in the inter-granular lanes in the solar photosphere, known as Bright
Points. It is highlighted the great presence of magnetic structures in
quiet Sun regions analyzed from different observational campaigns. The
density of BPs in the quiet Sun shows a decrease as we approach the
limb, with values of ≃q 1% at the centre (μ ≈ 1), and ≃q 0.2%
at μ ≈ 0.3. We also present the discovery of small vortexes detected
in the solar surface through the movement of BPs, with radii around 241
km and lifetimes longer than 5 minutes. Further analyses, comprising
longer time series and information from different solar layers, are
being performed aiming at a more in-depth knowledge of these phenomena.
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Title: Small magnetic bright structures in the quiet Sun
Authors: Domingo, V.; Cabello, I.; Blanco Rodríguez, J.
2013hsa7.conf..782D Altcode:
This work aims at further developing our knowledge of the ubiquitous
small scale magnetic structures of the solar surface, focusing on
the poles of the Sun. To get a clearer view of the situation at the
very high latitudes, we make use of the inclination of the solar axis
with respect to the ecliptic. We find the known continuous decrease of
the area covered by bright points from centre to limb. However, when
the solar rotation axis is inclined toward us there is an increase in
bright points areas coverage near the limb, i.e. near the poles.
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Title: Structure of Small Magnetic Elements in the Solar Atmosphere
Authors: Domingo, V.; Palacios, J.; Balmaceda, L. A.; Domínguez,
S. V.; Cabello, I.
2012ASPC..454...69D Altcode: 2012arXiv1209.0978D
High resolution images at different wavelengths, spectrograms and
magnetograms, representing different levels of the solar atmosphere
obtained with Hinode have been combined to study the 3-dimensional
structure of the small magnetic elements in relation to their
radiance. A small magnetic element is described as example of the study.
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Title: Observations of Vortex Motion in the Solar Photosphere Using
Hinode-SP Data
Authors: Palacios, J.; Balmaceda, L. A.; Domínguez, S. V.; Cabello,
I.; Domingo, V.
2012ASPC..454...51P Altcode: 2012arXiv1209.0190P
In this work, we focus in the magnetic evolution of a small
region as seen by Hinode-SP during the time interval of about one
hour. High-cadence LOS magnetograms and velocity maps were derived,
allowing the study of different small-scale processes such as the
formation/dissappearance of bright points accompanying the evolution
of an observed convective vortical motion.
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Title: First Results from the SUNRISE Mission
Authors: Solanki, S. K.; Barthol, P.; Danilovic, S.; Feller, A.;
Gandorfer, A.; Hirzberger, J.; Jafarzadeh, S.; Lagg, A.; Riethmüller,
T. L.; Schüssler, M.; Wiegelmann, T.; Bonet, J. A.; González,
M. J. M.; Pillet, V. M.; Khomenko, E.; Yelles Chaouche, L.; Iniesta,
J. C. d. T.; Domingo, V.; Palacios, J.; Knölker, M.; González,
N. B.; Borrero, J. M.; Berkefeld, T.; Franz, M.; Roth, M.; Schmidt,
W.; Steiner, O.; Title, A. M.
2012ASPC..455..143S Altcode:
The SUNRISE balloon-borne solar observatory consists of a 1m aperture
Gregory telescope, a UV filter imager, an imaging vector polarimeter,
an image stabilization system, and further infrastructure. The first
science flight of SUNRISE yielded high-quality data that reveal the
structure, dynamics, and evolution of solar convection, oscillations,
and magnetic fields at a resolution of around 100 km in the quiet
Sun. Here we describe very briefly the mission and the first results
obtained from the SUNRISE data, which include a number of discoveries.
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Title: Detection of Vortex Tubes in Solar Granulation from
Observations SUNRISE
Authors: Steiner, O.; Franz, M.; González, N. B.; Nutto, C.; Rezaei,
R.; Pillet, V. M.; Bonet, J. A.; Iniesta, J. C. d. T.; Domingo, V.;
Solanki, S. K.; Knölker, M.; Schmidt, W.; Barthol, P.; Gandorfer, A.
2012ASPC..455...35S Altcode:
We investigated a time series of continuum intensity maps and
Dopplergrams of granulation in a very quiet solar region at the disk
center, recorded with the Imaging Magnetograph eXperiment (IMaX)
on board the balloon-borne solar observatory SUNRISE. We find that
granules frequently show substructure in the form of lanes composed of
a leading bright rim and a trailing dark edge, which move together
from the boundary of a granule into the granule itself. We find
strikingly similar events in synthesized intensity maps from an ab
initio numerical simulation of solar surface convection. We conclude
that these granular lanes are the visible signature of (horizontally
oriented) vortex tubes. The characteristic optical appearance of vortex
tubes at the solar surface is explained. This paper is a summary and
update of the results previously presented in Steiner et al. (2010).
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Title: Supersonic Magnetic Flows in the Quiet Sun Observed with
SUNRISE/IMaX
Authors: Borrero, J. M.; Pillet, V. M.; Schlichenmaier, R.; Schmidt,
W.; Berkefeld, T.; Solanki, S. K.; Bonet, J. A.; Iniesta, J. C. d. T.;
Domingo, V.; Barthol, P.; Gandorfer, A.
2012ASPC..455..155B Altcode: 2012arXiv1202.4354B
In this contribution we describe some recent observations of high-speed
magnetized flows in the quiet Sun granulation. These observations
were carried out with the Imaging Magnetograph eXperiment (IMaX)
onboard the stratospheric balloon SUNRISE, and possess an unprecedented
spatial resolution and temporal cadence. These flows were identified as
highly shifted circular polarization (Stokes V) signals. We estimate
the LOS velocity responsible for these shifts to be larger than 6 km
s<SUP>-1</SUP>, and therefore we refer to them as supersonic magnetic
flows. The average lifetime of the detected events is 81.3 s and
they occupy an average area of about 23 000 km<SUP>2</SUP>. Most of
the events occur within granular cells and correspond therefore to
upflows. However some others occur in intergranular lanes or bear no
clear relation to the convective velocity pattern. We analyze a number
of representative examples and discuss them in terms of magnetic loops,
reconnection events, and convective collapse.
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Title: Actinide and Ultra-Heavy Abundances in the Local Galactic
Cosmic Rays: An Analysis of the Results from the LDEF Ultra-Heavy
Cosmic-Ray Experiment
Authors: Donnelly, J.; Thompson, A.; O'Sullivan, D.; Daly, J.; Drury,
L.; Domingo, V.; Wenzel, K. -P.
2012ApJ...747...40D Altcode:
The LDEF Ultra-Heavy Cosmic-Ray Experiment (UHCRE) detected
Galactic cosmic rays (GCRs) of charge Z >= 70 in Earth orbit
with an exposure factor of 170 m<SUP>2</SUP> sr yr, much larger
than any other experiment. The major results include the first
statistically significant uniform sample of GCR actinides with
35 events passing quality cuts, evidence for the existence of
transuranic nuclei in the GCR with one <SUB>96</SUB>Cm candidate
event, and a low <SUB>82</SUB>Pb/<SUB>78</SUB>Pt ratio consistent
with other experiments. The probability of the existence of a
transuranic component is estimated as 96%, while the most likely
<SUB>92</SUB>U/<SUB>90</SUB>Th ratio is found to be 0.4 within a wide
70% confidence interval ranging from 0 to 0.96. Overall, the results are
consistent with a volatility-based acceleration bias and source material
which is mainly ordinary interstellar medium material with some recent
contamination by freshly synthesized material. Uncertainty in the key
<SUB>92</SUB>U/<SUB>90</SUB>Th ratio is dominated by statistical errors
resulting from the small sample size and any improved determination
will thus require an experiment with a substantially larger exposure
factor than the UHCRE.
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Title: Magnetic field emergence in mesogranular-sized exploding
granules observed with sunrise/IMaX data
Authors: Palacios, J.; Blanco Rodríguez, J.; Vargas Domínguez, S.;
Domingo, V.; Martínez Pillet, V.; Bonet, J. A.; Bellot Rubio, L. R.;
Del Toro Iniesta, J. C.; Solanki, S. K.; Barthol, P.; Gandorfer, A.;
Berkefeld, T.; Schmidt, W.; Knölker, M.
2012A&A...537A..21P Altcode: 2011arXiv1110.4555P
We report on magnetic field emergences covering significant
areas of exploding granules. The balloon-borne mission Sunrise
provided high spatial and temporal resolution images of the solar
photosphere. Continuum images, longitudinal and transverse magnetic
field maps and Dopplergrams obtained by IMaX onboard Sunrise are
analyzed by local correlation traking (LCT), divergence calculation
and time slices, Stokes inversions and numerical simulations are also
employed. We characterize two mesogranular-scale exploding granules
where ~10<SUP>18</SUP> Mx of magnetic flux emerges. The emergence
of weak unipolar longitudinal fields (~100 G) start with a single
visible magnetic polarity, occupying their respective granules' top
and following the granular splitting. After a while, mixed polarities
start appearing, concentrated in downflow lanes. The events last around
20 min. LCT analyses confirm mesogranular scale expansion, displaying
a similar pattern for all the physical properties, and divergence
centers match between all of them. We found a similar behaviour
with the emergence events in a numerical MHD simulation. Granule
expansion velocities are around 1 kms<SUP>-1</SUP> while magnetic
patches expand at 0.65 kms<SUP>-1</SUP>. One of the analyzed events
evidences the emergence of a loop-like structure. Advection of
the emerging magnetic flux features is dominated by convective
motion resulting from the exploding granule due to the magnetic
field frozen in the granular plasma. Intensification of the
magnetic field occurs in the intergranular lanes, probably
because of being directed by the downflowing plasma. <P />Movies
associated to Figs. 2-4 are available in electronic form at <A
href="http://www.aanda.org">http://www.aanda.org</A>
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Title: Spatial distribution and statistical properties of small-scale
convective vortex-like motions in a quiet-Sun region
Authors: Vargas Domínguez, S.; Palacios, J.; Balmaceda, L.; Cabello,
I.; Domingo, V.
2011MNRAS.416..148V Altcode: 2011MNRAS.tmp.1046V; 2011arXiv1105.3092V
High-resolution observations of a quiet-Sun internetwork region taken
with the Solar 1-m Swedish Telescope in La Palma are analysed. We
determine the location of small-scale vortex motions in the solar
photospheric region by computing the horizontal proper motions
of small-scale structures on time-series of images. These plasma
convectively driven swirl motions are associated to (1) downdrafts
(that have been commonly explained as corresponding to sites where
the plasma is cooled down and hence returned to the interior below
the visible photospheric level) and (2) horizontal velocity vectors
converging on a central point. The sink cores are proved to be the final
destination of passive floats tracing plasma flows towards the centre
of each vortex. We establish the occurrence of these events to be 1.4
× 10<SUP>-3</SUP> and 1.6 × 10<SUP>-3</SUP> vortices Mm<SUP>-2</SUP>
min<SUP>-1</SUP>, respectively, for the two time-series analysed here.
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Title: The Sun at high resolution: first results from the Sunrise
mission
Authors: Solanki, S. K.; Barthol, P.; Danilovic, S.; Feller,
A.; Gandorfer, A.; Hirzberger, J.; Lagg, A.; Riethmüller, T. L.;
Schüssler, M.; Wiegelmann, T.; Bonet, J. A.; Pillet, V. Martínez;
Khomenko, E.; del Toro Iniesta, J. C.; Domingo, V.; Palacios, J.;
Knölker, M.; González, N. Bello; Borrero, J. M.; Berkefeld, T.;
Franz, M.; Roth, M.; Schmidt, W.; Steiner, O.; Title, A. M.
2011IAUS..273..226S Altcode:
The Sunrise balloon-borne solar observatory consists of a 1m aperture
Gregory telescope, a UV filter imager, an imaging vector polarimeter,
an image stabilization system and further infrastructure. The first
science flight of Sunrise yielded high-quality data that reveal the
structure, dynamics and evolution of solar convection, oscillations
and magnetic fields at a resolution of around 100 km in the quiet
Sun. Here we describe very briefly the mission and the first results
obtained from the Sunrise data, which include a number of discoveries.
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Title: The Imaging Magnetograph eXperiment (IMaX) for the Sunrise
Balloon-Borne Solar Observatory
Authors: Martínez Pillet, V.; del Toro Iniesta, J. C.;
Álvarez-Herrero, A.; Domingo, V.; Bonet, J. A.; González Fernández,
L.; López Jiménez, A.; Pastor, C.; Gasent Blesa, J. L.; Mellado, P.;
Piqueras, J.; Aparicio, B.; Balaguer, M.; Ballesteros, E.; Belenguer,
T.; Bellot Rubio, L. R.; Berkefeld, T.; Collados, M.; Deutsch, W.;
Feller, A.; Girela, F.; Grauf, B.; Heredero, R. L.; Herranz, M.;
Jerónimo, J. M.; Laguna, H.; Meller, R.; Menéndez, M.; Morales, R.;
Orozco Suárez, D.; Ramos, G.; Reina, M.; Ramos, J. L.; Rodríguez,
P.; Sánchez, A.; Uribe-Patarroyo, N.; Barthol, P.; Gandorfer, A.;
Knoelker, M.; Schmidt, W.; Solanki, S. K.; Vargas Domínguez, S.
2011SoPh..268...57M Altcode: 2010SoPh..tmp..181M; 2010arXiv1009.1095M
The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter
built by four institutions in Spain that flew on board the Sunrise
balloon-borne solar observatory in June 2009 for almost six days over
the Arctic Circle. As a polarimeter, IMaX uses fast polarization
modulation (based on the use of two liquid crystal retarders),
real-time image accumulation, and dual-beam polarimetry to reach
polarization sensitivities of 0.1%. As a spectrograph, the instrument
uses a LiNbO<SUB>3</SUB> etalon in double pass and a narrow band
pre-filter to achieve a spectral resolution of 85 mÅ. IMaX uses the
high-Zeeman-sensitive line of Fe I at 5250.2 Å and observes all four
Stokes parameters at various points inside the spectral line. This
allows vector magnetograms, Dopplergrams, and intensity frames to be
produced that, after reconstruction, reach spatial resolutions in the
0.15 - 0.18 arcsec range over a 50×50 arcsec field of view. Time
cadences vary between 10 and 33 s, although the shortest one only
includes longitudinal polarimetry. The spectral line is sampled in
various ways depending on the applied observing mode, from just two
points inside the line to 11 of them. All observing modes include
one extra wavelength point in the nearby continuum. Gauss equivalent
sensitivities are 4 G for longitudinal fields and 80 G for transverse
fields per wavelength sample. The line-of-sight velocities are estimated
with statistical errors of the order of 5 - 40 m s<SUP>−1</SUP>. The
design, calibration, and integration phases of the instrument,
together with the implemented data reduction scheme, are described in
some detail.
---------------------------------------------------------
Title: The Sunrise Mission
Authors: Barthol, P.; Gandorfer, A.; Solanki, S. K.; Schüssler,
M.; Chares, B.; Curdt, W.; Deutsch, W.; Feller, A.; Germerott, D.;
Grauf, B.; Heerlein, K.; Hirzberger, J.; Kolleck, M.; Meller, R.;
Müller, R.; Riethmüller, T. L.; Tomasch, G.; Knölker, M.; Lites,
B. W.; Card, G.; Elmore, D.; Fox, J.; Lecinski, A.; Nelson, P.;
Summers, R.; Watt, A.; Martínez Pillet, V.; Bonet, J. A.; Schmidt,
W.; Berkefeld, T.; Title, A. M.; Domingo, V.; Gasent Blesa, J. L.;
del Toro Iniesta, J. C.; López Jiménez, A.; Álvarez-Herrero, A.;
Sabau-Graziati, L.; Widani, C.; Haberler, P.; Härtel, K.; Kampf,
D.; Levin, T.; Pérez Grande, I.; Sanz-Andrés, A.; Schmidt, E.
2011SoPh..268....1B Altcode: 2010arXiv1009.2689B; 2010SoPh..tmp..224B
The first science flight of the balloon-borne Sunrise telescope took
place in June 2009 from ESRANGE (near Kiruna/Sweden) to Somerset
Island in northern Canada. We describe the scientific aims and
mission concept of the project and give an overview and a description
of the various hardware components: the 1-m main telescope with its
postfocus science instruments (the UV filter imager SuFI and the imaging
vector magnetograph IMaX) and support instruments (image stabilizing
and light distribution system ISLiD and correlating wavefront sensor
CWS), the optomechanical support structure and the instrument mounting
concept, the gondola structure and the power, pointing, and telemetry
systems, and the general electronics architecture. We also explain
the optimization of the structural and thermal design of the complete
payload. The preparations for the science flight are described,
including AIV and ground calibration of the instruments. The course
of events during the science flight is outlined, up to the recovery
activities. Finally, the in-flight performance of the instrumentation
is discussed.
---------------------------------------------------------
Title: SUNRISE: Instrument, Mission, Data, and First Results
Authors: Solanki, S. K.; Barthol, P.; Danilovic, S.; Feller, A.;
Gandorfer, A.; Hirzberger, J.; Riethmüller, T. L.; Schüssler, M.;
Bonet, J. A.; Martínez Pillet, V.; del Toro Iniesta, J. C.; Domingo,
V.; Palacios, J.; Knölker, M.; Bello González, N.; Berkefeld, T.;
Franz, M.; Schmidt, W.; Title, A. M.
2010ApJ...723L.127S Altcode: 2010arXiv1008.3460S
The SUNRISE balloon-borne solar observatory consists of a 1 m aperture
Gregory telescope, a UV filter imager, an imaging vector polarimeter,
an image stabilization system, and further infrastructure. The first
science flight of SUNRISE yielded high-quality data that revealed the
structure, dynamics, and evolution of solar convection, oscillations,
and magnetic fields at a resolution of around 100 km in the quiet
Sun. After a brief description of instruments and data, the first
qualitative results are presented. In contrast to earlier observations,
we clearly see granulation at 214 nm. Images in Ca II H display narrow,
short-lived dark intergranular lanes between the bright edges of
granules. The very small-scale, mixed-polarity internetwork fields
are found to be highly dynamic. A significant increase in detectable
magnetic flux is found after phase-diversity-related reconstruction
of polarization maps, indicating that the polarities are mixed right
down to the spatial resolution limit and probably beyond.
---------------------------------------------------------
Title: Supersonic Magnetic Upflows in Granular Cells Observed with
SUNRISE/IMAX
Authors: Borrero, J. M.; Martínez-Pillet, V.; Schlichenmaier, R.;
Solanki, S. K.; Bonet, J. A.; del Toro Iniesta, J. C.; Schmidt, W.;
Barthol, P.; Gandorfer, A.; Domingo, V.; Knölker, M.
2010ApJ...723L.144B Altcode: 2010arXiv1009.1227B
Using the IMaX instrument on board the SUNRISE stratospheric balloon
telescope, we have detected extremely shifted polarization signals
around the Fe I 5250.217 Å spectral line within granules in the solar
photosphere. We interpret the velocities associated with these events
as corresponding to supersonic and magnetic upflows. In addition, they
are also related to the appearance of opposite polarities and highly
inclined magnetic fields. This suggests that they are produced by the
reconnection of emerging magnetic loops through granular upflows. The
events occupy an average area of 0.046 arcsec<SUP>2</SUP> and last for
about 80 s, with larger events having longer lifetimes. These supersonic
events occur at a rate of 1.3 × 10<SUP>-5</SUP> occurrences per second
per arcsec<SUP>2</SUP>.
---------------------------------------------------------
Title: Detection of Vortex Tubes in Solar Granulation from
Observations with SUNRISE
Authors: Steiner, O.; Franz, M.; Bello González, N.; Nutto, Ch.;
Rezaei, R.; Martínez Pillet, V.; Bonet Navarro, J. A.; del Toro
Iniesta, J. C.; Domingo, V.; Solanki, S. K.; Knölker, M.; Schmidt,
W.; Barthol, P.; Gandorfer, A.
2010ApJ...723L.180S Altcode: 2010arXiv1009.4723S
We have investigated a time series of continuum intensity maps and
corresponding Dopplergrams of granulation in a very quiet solar region
at the disk center, recorded with the Imaging Magnetograph eXperiment
(IMaX) on board the balloon-borne solar observatory SUNRISE. We
find that granules frequently show substructure in the form of lanes
composed of a leading bright rim and a trailing dark edge, which move
together from the boundary of a granule into the granule itself. We
find strikingly similar events in synthesized intensity maps from an
ab initio numerical simulation of solar surface convection. From cross
sections through the computational domain of the simulation, we conclude
that these granular lanes are the visible signature of (horizontally
oriented) vortex tubes. The characteristic optical appearance of vortex
tubes at the solar surface is explained. We propose that the observed
vortex tubes may represent only the large-scale end of a hierarchy of
vortex tubes existing near the solar surface.
---------------------------------------------------------
Title: Where the Granular Flows Bend
Authors: Khomenko, E.; Martínez Pillet, V.; Solanki, S. K.; del Toro
Iniesta, J. C.; Gandorfer, A.; Bonet, J. A.; Domingo, V.; Schmidt,
W.; Barthol, P.; Knölker, M.
2010ApJ...723L.159K Altcode: 2010arXiv1008.0517K
Based on IMaX/SUNRISE data, we report on a previously undetected
phenomenon in solar granulation. We show that in a very narrow region
separating granules and intergranular lanes, the spectral line width
of the Fe I 5250.2 Å line becomes extremely small. We offer an
explanation of this observation with the help of magneto-convection
simulations. These regions with extremely small line widths correspond
to the places where the granular flows bend from upflow in granules
to downflow in intergranular lanes. We show that the resolution and
image stability achieved by IMaX/SUNRISE are important requisites to
detect this interesting phenomenon.
---------------------------------------------------------
Title: Bright Points in the Quiet Sun as Observed in the Visible
and Near-UV by the Balloon-borne Observatory SUNRISE
Authors: Riethmüller, T. L.; Solanki, S. K.; Martínez Pillet, V.;
Hirzberger, J.; Feller, A.; Bonet, J. A.; Bello González, N.; Franz,
M.; Schüssler, M.; Barthol, P.; Berkefeld, T.; del Toro Iniesta,
J. C.; Domingo, V.; Gandorfer, A.; Knölker, M.; Schmidt, W.
2010ApJ...723L.169R Altcode: 2010arXiv1009.1693R
Bright points (BPs) are manifestations of small magnetic elements
in the solar photosphere. Their brightness contrast not only gives
insight into the thermal state of the photosphere (and chromosphere) in
magnetic elements, but also plays an important role in modulating the
solar total and spectral irradiance. Here, we report on simultaneous
high-resolution imaging and spectropolarimetric observations of
BPs using SUNRISE balloon-borne observatory data of the quiet Sun
at the disk center. BP contrasts have been measured between 214 nm
and 525 nm, including the first measurements at wavelengths below
388 nm. The histograms of the BP peak brightness show a clear trend
toward broader contrast distributions and higher mean contrasts at
shorter wavelengths. At 214 nm, we observe a peak brightness of up to
five times the mean quiet-Sun value, the highest BP contrast so far
observed. All BPs are associated with a magnetic signal, although in
a number of cases it is surprisingly weak. Most of the BPs show only
weak downflows, the mean value being 240 m s<SUP>-1</SUP>, but some
display strong down- or upflows reaching a few km s<SUP>-1</SUP>.
---------------------------------------------------------
Title: Transverse Component of the Magnetic Field in the Solar
Photosphere Observed by SUNRISE
Authors: Danilovic, S.; Beeck, B.; Pietarila, A.; Schüssler, M.;
Solanki, S. K.; Martínez Pillet, V.; Bonet, J. A.; del Toro Iniesta,
J. C.; Domingo, V.; Barthol, P.; Berkefeld, T.; Gandorfer, A.;
Knölker, M.; Schmidt, W.; Title, A. M.
2010ApJ...723L.149D Altcode: 2010arXiv1008.1535D
We present the first observations of the transverse component of
a photospheric magnetic field acquired by the imaging magnetograph
SUNRISE/IMaX. Using an automated detection method, we obtain statistical
properties of 4536 features with significant linear polarization
signal. We obtain a rate of occurrence of 7 × 10<SUP>-4</SUP>
s<SUP>-1</SUP> arcsec<SUP>-2</SUP>, which is 1-2 orders of magnitude
larger than the values reported by previous studies. We show that
these features have no characteristic size or lifetime. They appear
preferentially at granule boundaries with most of them being caught
in downflow lanes at some point. Only a small percentage are entirely
and constantly embedded in upflows (16%) or downflows (8%).
---------------------------------------------------------
Title: Detection of Large Acoustic Energy Flux in the Solar Atmosphere
Authors: Bello González, N.; Franz, M.; Martínez Pillet, V.; Bonet,
J. A.; Solanki, S. K.; del Toro Iniesta, J. C.; Schmidt, W.; Gandorfer,
A.; Domingo, V.; Barthol, P.; Berkefeld, T.; Knölker, M.
2010ApJ...723L.134B Altcode: 2010arXiv1009.4795B
We study the energy flux carried by acoustic waves excited by convective
motions at sub-photospheric levels. The analysis of high-resolution
spectropolarimetric data taken with IMaX/SUNRISE provides a total
energy flux of ~6400-7700 W m<SUP>-2</SUP> at a height of ~250 km
in the 5.2-10 mHz range, i.e., at least twice the largest energy
flux found in previous works. Our estimate lies within a factor of
two of the energy flux needed to balance radiative losses from the
chromosphere according to the estimates of Anderson & Athay and
revives interest in acoustic waves for transporting energy to the
chromosphere. The acoustic flux is mainly found in the intergranular
lanes but also in small rapidly evolving granules and at the bright
borders, forming dark dots and lanes of splitting granules.
---------------------------------------------------------
Title: Magnetic Loops in the Quiet Sun
Authors: Wiegelmann, T.; Solanki, S. K.; Borrero, J. M.; Martínez
Pillet, V.; del Toro Iniesta, J. C.; Domingo, V.; Bonet, J. A.;
Barthol, P.; Gandorfer, A.; Knölker, M.; Schmidt, W.; Title, A. M.
2010ApJ...723L.185W Altcode: 2010arXiv1009.4715W
We investigate the fine structure of magnetic fields in the atmosphere
of the quiet Sun. We use photospheric magnetic field measurements from
SUNRISE/IMaX with unprecedented spatial resolution to extrapolate
the photospheric magnetic field into higher layers of the solar
atmosphere with the help of potential and force-free extrapolation
techniques. We find that most magnetic loops that reach into the
chromosphere or higher have one footpoint in relatively strong magnetic
field regions in the photosphere. Ninety-one percent of the magnetic
energy in the mid-chromosphere (at a height of 1 Mm) is in field
lines, whose stronger footpoint has a strength of more than 300 G,
i.e., above the equipartition field strength with convection. The
loops reaching into the chromosphere and corona are also found to be
asymmetric in the sense that the weaker footpoint has a strength B <
300 G and is located in the internetwork (IN). Such loops are expected
to be strongly dynamic and have short lifetimes, as dictated by the
properties of the IN fields.
---------------------------------------------------------
Title: SUNRISE/IMaX Observations of Convectively Driven Vortex Flows
in the Sun
Authors: Bonet, J. A.; Márquez, I.; Sánchez Almeida, J.; Palacios,
J.; Martínez Pillet, V.; Solanki, S. K.; del Toro Iniesta, J. C.;
Domingo, V.; Berkefeld, T.; Schmidt, W.; Gandorfer, A.; Barthol, P.;
Knölker, M.
2010ApJ...723L.139B Altcode: 2010arXiv1009.1992B
We characterize the observational properties of the convectively driven
vortex flows recently discovered on the quiet Sun, using magnetograms,
Dopplergrams, and images obtained with the 1 m balloon-borne SUNRISE
telescope. By visual inspection of time series, we find some 3.1
× 10<SUP>-3</SUP> vortices Mm<SUP>-2</SUP> minute<SUP>-1</SUP>,
which is a factor of ~1.7 larger than previous estimates. The mean
duration of the individual events turns out to be 7.9 minutes, with
a standard deviation of 3.2 minutes. In addition, we find several
events appearing at the same locations along the duration of the time
series (31.6 minutes). Such recurrent vortices show up in the proper
motion flow field map averaged over the time series. The typical
vertical vorticities are lsim6 × 10<SUP>-3</SUP> s<SUP>-1</SUP>,
which corresponds to a period of rotation of some 35 minutes. The
vortices show a preferred counterclockwise sense of rotation, which
we conjecture may have to do with the preferred vorticity impinged by
the solar differential rotation.
---------------------------------------------------------
Title: Surface Waves in Solar Granulation Observed with SUNRISE
Authors: Roth, M.; Franz, M.; Bello González, N.; Martínez Pillet,
V.; Bonet, J. A.; Gandorfer, A.; Barthol, P.; Solanki, S. K.;
Berkefeld, T.; Schmidt, W.; del Toro Iniesta, J. C.; Domingo, V.;
Knölker, M.
2010ApJ...723L.175R Altcode: 2010arXiv1009.4790R
Solar oscillations are expected to be excited by turbulent flows in
the intergranular lanes near the solar surface. Time series recorded
by the IMaX instrument on board the SUNRISE observatory reveal solar
oscillations at high spatial resolution, which allow the study of
the properties of oscillations with short wavelengths. We analyze
two time series with synchronous recordings of Doppler velocity and
continuum intensity images with durations of 32 minutes and 23 minutes,
respectively, recorded close to the disk center of the Sun to study
the propagation and excitation of solar acoustic oscillations. In
the Doppler velocity data, both the standing acoustic waves and the
short-lived, high-degree running waves are visible. The standing
waves are visible as temporary enhancements of the amplitudes of the
large-scale velocity field due to the stochastic superposition of
the acoustic waves. We focus on the high-degree small-scale waves by
suitable filtering in the Fourier domain. Investigating the propagation
and excitation of f- and p <SUB>1</SUB>-modes with wavenumbers k>1.4
Mm<SUP>-1</SUP>, we also find that exploding granules contribute to
the excitation of solar p-modes in addition to the contribution of
intergranular lanes.
---------------------------------------------------------
Title: Fully Resolved Quiet-Sun Magnetic flux Tube Observed with
the SUNRISE/IMAX Instrument
Authors: Lagg, A.; Solanki, S. K.; Riethmüller, T. L.; Martínez
Pillet, V.; Schüssler, M.; Hirzberger, J.; Feller, A.; Borrero,
J. M.; Schmidt, W.; del Toro Iniesta, J. C.; Bonet, J. A.; Barthol, P.;
Berkefeld, T.; Domingo, V.; Gandorfer, A.; Knölker, M.; Title, A. M.
2010ApJ...723L.164L Altcode: 2010arXiv1009.0996L
Until today, the small size of magnetic elements in quiet-Sun areas has
required the application of indirect methods, such as the line-ratio
technique or multi-component inversions, to infer their physical
properties. A consistent match to the observed Stokes profiles could
only be obtained by introducing a magnetic filling factor that specifies
the fraction of the observed pixel filled with magnetic field. Here,
we investigate the properties of a small magnetic patch in the quiet
Sun observed with the IMaX magnetograph on board the balloon-borne
telescope SUNRISE with unprecedented spatial resolution and low
instrumental stray light. We apply an inversion technique based on
the numerical solution of the radiative transfer equation to retrieve
the temperature stratification and the field strength in the magnetic
patch. The observations can be well reproduced with a one-component,
fully magnetized atmosphere with a field strength exceeding 1 kG and
a significantly enhanced temperature in the mid to upper photosphere
with respect to its surroundings, consistent with semi-empirical flux
tube models for plage regions. We therefore conclude that, within the
framework of a simple atmospheric model, the IMaX measurements resolve
the observed quiet-Sun flux tube.
---------------------------------------------------------
Title: The IMaX polarimeter for the solar telescope SUNRISE of the
NASA long duration balloon program
Authors: Alvarez-Herrero, A.; Martínez-Pillet, V.; Del Toro Iniesta,
J. C.; Domingo, V.
2010EPJWC...505002A Altcode:
On June 8th 2009 the SUNRISE mission was successfully launched. This
mission consisted of a 1m aperture solar telescope on board of a
stratospheric balloon within the Long Duration Balloon NASA program. The
flight followed the foreseen circumpolar trajectory over the Artic
and the duration was 5 days and 17 hours. One of the two postfocal
instruments onboard was IMaX, the Imaging Magnetograph eXperiment. This
instrument is a solar magnetograph which is a diffraction limited imager
capable to resolve 100 km on the solar surface, and simultaneously
a high sensitivity polarimeter (<10<SUP>-3</SUP>) and a high
resolution spectrograph (bandwidth <70mÅ). The magnetic vectorial
map can be extracted thanks to the well-know Zeeman effect, which takes
place in the solar atoms, allowing to relate polarization and spectral
measurements to magnetic fields. The technological challenge of the IMaX
development has a special relevance due to the utilization of innovative
technologies in the Aeroespacial field and it is an important precedent
for future space missions such as Solar Orbiter from ESA. Among these
novel technologies the utilization of Liquid Crystal Variable Retarders
(LCVRs) as polarization modulators and a LiNbO<SUB>3</SUB> etalon as
tunable spectral filter are remarkable. Currently the data obtained
is being analyzed and the preliminary results show unprecedented
information about the solar dynamics.
---------------------------------------------------------
Title: Evidence of small-scale magnetic concentrations dragged by
vortex motion of solar photospheric plasma
Authors: Balmaceda, L.; Vargas Domínguez, S.; Palacios, J.; Cabello,
I.; Domingo, V.
2010A&A...513L...6B Altcode: 2010arXiv1004.1185B
Vortex-type motions have been measured by tracking bright points in
high-resolution observations of the solar photosphere. These small-scale
motions are thought to be determinant in the evolution of magnetic
footpoints and their interaction with plasma and therefore likely to
play a role in heating the upper solar atmosphere by twisting magnetic
flux tubes. We report the observation of magnetic concentrations being
dragged towards the center of a convective vortex motion in the solar
photosphere from high-resolution ground-based and space-borne data. We
describe this event by analyzing a series of images at different solar
atmospheric layers. By computing horizontal proper motions, we detect a
vortex whose center appears to be the draining point for the magnetic
concentrations detected in magnetograms and well-correlated with the
locations of bright points seen in G-band and CN images.
---------------------------------------------------------
Title: Observations of Magnetic Elements in the Quiet Sun Internetwork
Authors: Balmaceda, L. A.; Palacios, J.; Cabello, I.; Domingo, V.
2009ASPC..415..156B Altcode:
We present here the analysis of high-resolution images of the quiet Sun
at disk center taken with the Solar Optical Telescope (SOT) on board
Hinode in the CN bandhead (388.35 nm) and magnetograms in the Mg I line
(517.27 nm). These observations are complemented with data from the
Swedish 1m Solar Telescope (SST). All data sets were obtained during
the Hinode/Canary Islands joint campaign (HOP 0014) in September,
2007. In particular, we investigate the morphology, radiative and
magnetic properties of small-scale elements in the solar atmosphere.
---------------------------------------------------------
Title: Solar Surface Magnetism and Irradiance on Time Scales from
Days to the 11-Year Cycle
Authors: Domingo, V.; Ermolli, I.; Fox, P.; Fröhlich, C.; Haberreiter,
M.; Krivova, N.; Kopp, G.; Schmutz, W.; Solanki, S. K.; Spruit, H. C.;
Unruh, Y.; Vögler, A.
2009SSRv..145..337D Altcode:
The uninterrupted measurement of the total solar irradiance during the
last three solar cycles and an increasing amount of solar spectral
irradiance measurements as well as solar imaging observations
(magnetograms and photometric data) have stimulated the development
of models attributing irradiance variations to solar surface
magnetism. Here we review the current status of solar irradiance
measurements and modelling efforts based on solar photospheric
magnetic fields. Thereby we restrict ourselves to the study of solar
variations from days to the solar cycle. Phenomenological models
of the solar atmosphere in combination with imaging observations of
solar electromagnetic radiation and measurements of the photospheric
magnetic field have reached high enough quality to show that a large
fraction (at least, about 80%) of the solar irradiance variability
can be explained by the radiative effects of the magnetic activity
present in the photosphere. Also, significant progress has been made
with magnetohydrodynamic simulations of convection that allow us to
relate the radiance of the photospheric magnetic structures to the
observations.
---------------------------------------------------------
Title: Convectively Driven Vortex Flows in the Sun
Authors: Bonet, J. A.; Márquez, I.; Sánchez Almeida, J.; Cabello,
I.; Domingo, V.
2008ApJ...687L.131B Altcode: 2008arXiv0809.3885B
We have discovered small whirlpools in the Sun, with a size similar to
terrestrial hurricanes (lesssim0.5 Mm). The theory of solar convection
predicts them, but they had remained elusive so far. The vortex flows
are created at the downdrafts where the plasma returns to the solar
interior after cooling down, and we detect them because some magnetic
bright points (BPs) follow a logarithmic spiral on their way to being
engulfed by a downdraft. Our disk-center observations show 0.9 ×
10<SUP>-2</SUP> vortexes per Mm<SUP>2</SUP>, with a lifetime of the
order of 5 minutes, and with no preferred sense of rotation. They are
not evenly spread out over the surface, but they seem to trace the
supergranulation and the mesogranulation. These observed properties are
strongly biased by our type of measurement, unable to detect vortexes
except when they are engulfing magnetic BPs.
---------------------------------------------------------
Title: Convectively driven vortex flows in the Sun
Authors: Bonet, J. A.; Márquez, I.; Sánchez Almeida, J.; Cabello,
I.; Domingo, V.
2008iac..talk..143B Altcode: 2008iac..talk...26B
No abstract at ADS
---------------------------------------------------------
Title: Small magnetic structures in the photosphere, radiative
properties
Authors: Palacios, Judith; Domingo, Vicente; Cabello, Iballa; Bonet,
José Antonio; Sánchez Almeida, Jorge
2008cosp...37.2331P Altcode: 2008cosp.meet.2331P
The three dimensional structure of small magnetic field features in the
photosphere, their dynamic behavior and their radiative properties are
studied. We analyze data obtained in simultaneous observations made on
Sept 29 and 30, 2007 with the HINODE spacecraft and the Swedish Solar
Telescope (SST) in La Palma in different wavelengths, such as CaII
(396.85 nm) and CN (388.35 nm) and other with Hinode data; and Gband
(430.56 nm) with SST. Tha analysis is completed with high resolution
Gband and Gcontinuum (436.39 nm) images from SST obtained on 2005 and
2006. Magnetograms have been obtained from both observatories. SST
images have been processed with MOMFB code. Ribbon-like structures and
"flowers" are studied in detail. Comparisons with solar atmospheric
models are presented.
---------------------------------------------------------
Title: The DynaMICS perspective
Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies,
S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.;
Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.;
Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat,
E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.;
Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes,
I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.;
Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.;
Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.;
Thompson, M.; Vauclair, S.; Zahn, J. P.
2006ESASP.624E..24T Altcode: 2006soho...18E..24T
No abstract at ADS
---------------------------------------------------------
Title: Scientific Objectives of the Novel Formation Flying Mission
Aspiics
Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies,
S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.;
Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.;
Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat,
E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.;
Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes,
I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.;
Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.;
Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.;
Thompson, M.; Vauclair, S.; Zahn, J. P.
2006ESASP.617E.164L Altcode: 2006soho...17E.164L
No abstract at ADS
---------------------------------------------------------
Title: The EUV Variability Experiment (EVE) on the Solar Dynamics
Observatory (SDO): Science Plan and Instrument Overview
Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies,
S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.;
Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.;
Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat,
E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.;
Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes,
I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.;
Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.;
Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.;
Thompson, M.; Vauclair, S.; Zahn, J. P.
2006ESASP.617E.165W Altcode: 2006soho...17E.165W
No abstract at ADS
---------------------------------------------------------
Title: The Dynamics Project
Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies,
S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.;
Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.;
Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat,
E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.;
Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes,
I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.;
Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.;
Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.;
Thompson, M.; Vauclair, S.; Zahn, J. P.
2006ESASP.617E.162T Altcode: 2006soho...17E.162T
No abstract at ADS
---------------------------------------------------------
Title: Solar Photospheric Magnetic Elements Dimension and Radiance
Authors: Cabello, I.; Domingo, V.
2006ESASP.617E..55C Altcode: 2006soho...17E..55C
No abstract at ADS
---------------------------------------------------------
Title: Detailed design of the imaging magnetograph experiment (IMaX):
a visible imager magnetograph for the Sunrise mission
Authors: Álvarez-Herrero, A.; Belenguer, T.; Pastor, C.; González,
L.; Heredero, R. L.; Ramos, G.; Reina, M.; Sánchez, A.; Villanueva,
J.; Sabau, L.; Martínez Pillet, V.; Bonet, J. A.; Collados, M.;
Jochum, L.; Ballesteros, E.; Medina Trujillo, J. L.; Ruiz, Cobo B.;
González, J. C.; del Toro Iniesta, J. C.; López Jiménez, A. C.;
Castillo Lorenzo, J.; Herranz, M.; Jerónimo, J. M.; Mellado, P.;
Morales, R.; Rodríguez, J.; Domingo, V.; Gasent, J. L.; Rodríquez, P.
2006SPIE.6265E..4CA Altcode: 2006SPIE.6265E.132A
In this work, it is described the Imaging Magnetograph eXperiment,
IMaX, one of the three postfocal instruments of the Sunrise mission. The
Sunrise project consists on a stratospheric balloon with a 1 m aperture
telescope, which will fly from the Antarctica within the NASA Long
Duration Balloon Program. IMaX will provide vector magnetograms
of the solar surface with a spatial resolution of 70 m. This data
is relevant for understanding how the magnetic fields emerge in
the solar surface, how they couple the photospheric base with the
million degrees of temperature of the solar corona and which are the
processes that are responsible of the generation of such an immense
temperatures. To meet this goal IMaX should work as a high sensitivity
polarimeter, high resolution spectrometer and a near diffraction
limited imager. Liquid Crystal Variable Retarders will be used as
polarization modulators taking advantage of the optical retardation
induced by application of low electric fields and avoiding mechanical
mechanisms. Therefore, the interest of these devices for aerospace
applications is envisaged. The spectral resolution required will be
achieved by using a LiNbO <SUB>3</SUB> Fabry-Perot etalon in double
pass configuration as spectral filter before the two CCDs detectors. As
well phase-diversity techniques will be implemented in order to improve
the image quality. Nowadays, IMaX project is in the detailed design
phase before fabrication, integration, assembly and verification. This
paper briefly describes the current status of the instrument and the
technical solutions developed to fulfil the scientific requirements.
---------------------------------------------------------
Title: The intensity contrast of solar photospheric faculae and
network elements. II. Evolution over the rising phase of solar
cycle 23
Authors: Ortiz, A.; Domingo, V.; Sanahuja, B.
2006A&A...452..311O Altcode: 2006astro.ph..2556O
We studied the radiative properties of small magnetic elements (active
region faculae and the network) during the rising phase of solar cycle
23 from 1996 to 2001, determining their contrasts as a function of
heliocentric angle, magnetogram signal, and the solar cycle phase. We
combined near-simultaneous full disk images of the line-of-sight
magnetic field and photospheric continuum intensity provided by the
MDI instrument on board the SOHO spacecraft. Sorting the magnetogram
signal into different ranges allowed us to distinguish between the
contrast of different magnetic structures. We find that the contrast
center-to-limb variation (CLV) of these small magnetic elements is
independent of time with a 10% precision, when measured during the
rising phase of solar cycle 23. A 2-dimensional empirical expression
for the contrast of photospheric features as a function of both the
position on the disk and the averaged magnetic field strength was
determined, showing its validity through the studied time period. A
study of the relationship between magnetogram signal and the peak
contrasts shows that the intrinsic contrast (maximum contrast per unit
of magnetic flux) of network flux tubes is higher than that of active
region faculae during the solar cycle.
---------------------------------------------------------
Title: Centre-to-limb variation of photospheric facular radiance
and image resolution
Authors: Domingo, Vicente; Ortiz, Ada; Sanahuja, Blai; Cabello, Iballa
2005AdSpR..35..345D Altcode:
We study the effect of the angular resolution on the determination
of the angular properties of the facular radiance. We analyze
photospheric intensity in the continuum, around the Ni 676.8 nm line,
and longitudinal magnetic field along the line of sight, measured by
the MDI instrument aboard SOHO with two spatial resolutions, 4″ and
1.2″ (2″ and 0.6″ pixels, respectively). The effect of the limited
photometric sensitivity of the instrument and the limited information on
the angular structure of the magnetic field tubes are considered. Our
study of the high-resolution data shows that intensity contrast of
magnetic features between 80 and 600 Gauss increases from centre to
limb up to a maximum that occurs at higher heliocentric angles ( θ)
when obtained with higher resolution data than for lower resolution
data. There is a suggestion that at heliocentric angles below about
75° there is only a monotonic increase in the contrast as one goes
from cos ( θ) = 1 to cos ( θ) = 0.2.
---------------------------------------------------------
Title: The imaging magnetograph eXperiment for the SUNRISE balloon
Antarctica project
Authors: Martinez Pillet, Valentin; Bonet, Jose A.; Collados, Manuel
V.; Jochum, Lieselotte; Mathew, S.; Medina Trujillo, J. L.; Ruiz Cobo,
B.; del Toro Iniesta, Jose Carlos; Lopez Jimenez, A. C.; Castillo
Lorenzo, J.; Herranz, M.; Jeronimo, J. M.; Mellado, P.; Morales, R.;
Rodriguez, J.; Alvarez-Herrero, Alberto; Belenguer, Tomas; Heredero,
R. L.; Menendez, M.; Ramos, G.; Reina, Manuel; Pastor, C.; Sanchez,
A.; Villanueva, J.; Domingo, Vicente; Gasent, J. L.; Rodriguez, P.
2004SPIE.5487.1152M Altcode:
The SUNRISE balloon project is a high-resolution mission to study solar
magnetic fields able to resolve the critical scale of 100 km in the
solar photosphere, or about one photon mean free path. The Imaging
Magnetograph eXperiment (IMaX) is one of the three instruments that
will fly in the balloon and will receive light from the 1m aperture
telescope of the mission. IMaX should take advantage of the 15 days
of uninterrupted solar observations and the exceptional resolution
to help clarifying our understanding of the small-scale magnetic
concentrations that pervade the solar surface. For this, IMaX should
act as a diffraction limited imager able to carry out spectroscopic
analysis with resolutions in the 50.000-100.000 range and capable
to perform polarization measurements. The solutions adopted by the
project to achieve all these three demanding goals are explained in this
article. They include the use of Liquid Crystal Variable Retarders for
the polarization modulation, one LiNbO<SUB>3</SUB> etalon in double pass
and two modern CCD detectors that allow for the application of phase
diversity techniques by slightly changing the focus of one of the CCDs.
---------------------------------------------------------
Title: Excess facular emission from an isolated active region during
solar minimum: the example of NOAA AR 7978
Authors: Ortiz, A.; Domingo, V.; Sanahuja, B.; Fröhlich, C.
2004JASTP..66...67O Altcode: 2004JATP...66...67O
The facular contribution to solar irradiance variations on the short
time scale is studied by analyzing a simple case of an isolated active
region that crossed the solar disk during the 1996 minimum of activity,
NOAA AR 7978. Its passage during several Carrington rotations,
specifically from rotation 1911 to 1916, allows us to analyze the
evolution of the angular distribution of the excess radiance of
the facular region using SOHO/VIRGO and MDI data. We associate this
evolution with the evolution of the extent corresponding to the isolated
active region as well as with the aging of the region itself. Finally,
we evaluate the total (i.e. in all directions) emission of this facular
region and its spectral and temporal evolution.
---------------------------------------------------------
Title: Magnetic field tubes emerging in the photosphere
Authors: Domingo, V.; Marco, E.; Ortiz, A.; Sanahuja, B.
2004cosp...35.4732D Altcode: 2004cosp.meet.4732D
Magnetic field tubes emerging in the photosphere are the dominant
contributors to the solar irradiance variations with time. The knowledge
of the radiative properties of the photospheric magnetic field elements
is, therefore, of high interest to understand the solar irradiance. A
classical way to quantify the angular distribution of their radiative
properties is the measurement of the contrast between their radiance
and the one from the surrounding photosphere as a function of
their heliocentric angle location, known as centre-to-limb-variation
(CLV). There are many published measurements of the CLV of photospheric
small magnetic elements, mostly faculae, made in different conditions
and giving different results. One of the parameters that may be
different from one observation to another is the angular resolution. We
study the effect of the angular resolution on the determination of
the angular properties of the facular radiance, with measurements
of photospheric intensity in the continuum, around the Fe 676.8 nm,
and of the longitudinal magnetic field, along the line of sight,
made with the MDI instrument aboard SOHO with two resolutions, 4 arc
seconds and 1.2 arc seconds (2 and 0.6 arc second pixels, respectively)
. The effect of the limited photometric sensitivity of the instrument
and the limited information on the angular structure of the magnetic
field tubes are considered.
---------------------------------------------------------
Title: Contribution of the small photospheric magnetic elements to
the long-term solar irradiance
Authors: Ortiz, Ada; Domingo, Vicente; Sanahuja, Blai
2003ESASP.535...43O Altcode: 2003iscs.symp...43O
We used near-simultaneous full disk magnetograms and images of the
photospheric continuum intensity provided by MDI/SOHO to analyze
the long-term evolution of the intensity contrast of small magnetic
features - faculae and magnetic network - as a function of position,
magnetic signal and time, from minimum to maximum of cycle 23. We
find that the spectral irradiance characteristics, at 676.8 nm, of
the small photospheric magnetic elements are practically invariable
throughout the rising phase of solar cycle 23. A preliminary statistical
analysis of the magnetic field suggests that the small magnetic elements
are likely to provide a significant contribution to the solar cycle
irradiance change.
---------------------------------------------------------
Title: IMax: a visible magnetograph for SUNRISE
Authors: Jochum, Lieselotte; Collados, Manuel; Martínez Pillet,
Valentin; Bonet, Jose A.; del Toro Iniesta, Jose Carlos; Lopez,
Antonio; Alvarez-Herrero, Alberto; Reina, Manuel; Fabregat, Juan;
Domingo, Vicente
2003SPIE.4843...20J Altcode:
The description of the Imaging Magnetograph eXperiment (IMaX) is
presented in this contribution. This is a magnetograph which will
fly by the end of 2006 on a stratospheric balloon, together with
other instruments (to be described elsewhere). Especial emphasis
is put on the scientific requirements to obtain diffraction-limited
visible magnetograms, on the optical design and several constraining
characteristics, such as the wavelength tuning or the crosstalk between
the Stokes parameters.
---------------------------------------------------------
Title: SOHO, Yohkoh, Ulysses and Trace: The four solar missions in
perspective, and available resources
Authors: Domingo, V.
2002Ap&SS.282..171D Altcode:
Four solar observing spacecraft, now in operation, have obtained and
continue to obtain data during the late phase of solar cycle 22 and
hopefully most of cycle 23. The data are available for scientific
analysis, practically in an unrestricted manner. A large pool of
software suited for the processing and to help programming any data
analysis is freely available. An almost random list of results that
are being obtained with this data is presented as an example of what
can be done by analysing the data from these spacecraft, either alone
or combining results among them, with ground observatories, or with
other spacecraft, such as those that measure particles and fields
in interplanetary space or in geospace, to study solar physics or
solar-terrestrial relations.
---------------------------------------------------------
Title: On the intensity contrast of solar photospheric faculae and
network elements
Authors: Ortiz, A.; Solanki, S. K.; Domingo, V.; Fligge, M.;
Sanahuja, B.
2002A&A...388.1036O Altcode: 2002astro.ph..7008O
Sunspots, faculae and the magnetic network contribute to solar
irradiance variations. The contribution due to faculae and the network
is of basic importance, but suffers from considerable uncertainty. We
determine the contrasts of active region faculae and the network,
both as a function of heliocentric angle and magnetogram signal. To
achieve this, we analyze near-simultaneous full disk images of
photospheric continuum intensity and line-of-sight magnetic field
provided by the Michelson Doppler Interferometer (MDI) on board
the SOHO spacecraft. Starting from the surface distribution of
the solar magnetic field we first construct a mask, which is then
used to determine the brightness of magnetic features, and the
relatively field-free part of the photosphere separately. By sorting
the magnetogram signal into different bins we are able to distinguish
between the contrasts of different concentrations of magnetic field. We
find that the center-to-limb variation (CLV) of the contrast changes
strongly with magnetogram signal. Thus, the contrasts of active region
faculae (large magnetogram signal) and the network (small signal)
exhibit a very different CLV, showing that the populations of magnetic
flux tubes that underly the two kinds of features are different. The
results are compatible with, on average, larger flux tubes in faculae
than in the network. This implies that these elements need to be treated
separately when reconstructing variations of the total solar irradiance
with high precision. We have obtained an analytical expression for
the contrast of photospheric magnetic features as a function of both
position on the disk and spatially averaged magnetic field strength,
by performing a 2-dimensional fit to the observations. We also provide
a linear relationship between magnetogram signal and the mu =cos (theta
), where theta is the heliocentric angle, at which the contrast is
maximal. Finally, we show that the maximum contrast per unit magnetic
flux decreases rapidly with increasing magnetogram signal, supporting
earlier evidence that the intrinsic contrast of magnetic flux tubes
in the network is higher.
---------------------------------------------------------
Title: Variation of the facular and network contrast during the
rising phase of cycle 23
Authors: Ortiz, A.; Domingo, V.; Sanahuja, B.; Solanki, S. K.
2002ESASP.508..185O Altcode: 2002soho...11..185O
Magnetic activity contributes to solar irradiance variations, both on
short and long time-scales. While sunspots and active region faculae
are the dominant contributors to irradiance changes on time-scales of
days to weeks, the origin of the long-term increase of the irradiance
between activity minimum and maximum (~0.1%) is still debated. It
has been proposed that the small-scale magnetic elements composing the
enhanced and quiet network contribute substantially to this increase. To
contribute to this debate, we attempt to see if there is a change in
the radiative properties of these elements along the solar cycle,
and to evaluate such a change. We use near-simultaneous full disk
magnetograms and images of the photospheric continuum intensity provided
by MDI/SOHO. We have studied the center-to-limb variations (CLV) of the
contrast as a function of magnetic strength and we are now analyzing how
the noise level of the images changes throughout time, as a preliminary
step towards an analysis of the temporal irradiance variations.
---------------------------------------------------------
Title: A first step towards proton flux forecasting
Authors: Aran, A.; Sanahuja, B.; Lario, D.; Domingo, V.
2002cosp...34E1078A Altcode: 2002cosp.meetE1078A
We present a preliminary version of a potential tool for real time
proton flux prediction which provides proton flux profiles and
cumulative fluence profiles at 0.5 MeV and 2 MeV of Solar Energetic
Particle (SEP) events, from their onset up to the arrival of the
interplanetary shock at the spacecraft position (located at 1 AU or
0.4 AU). Based on the proton transport model by Lario et al. (1998) and
the MHD shock propagation model of Wu et al. (1983), we have generated
a database containing "synthetic" profiles of the proton fluxes and
cumulative fluences of 384 SEP events. These events describe different
interplanetary scenarios which comprise a set of various MHD-shocks
and several heliolongitude locations of the solar activity sites, as
well as different conditions for particle transport. We are currently
validating the applicability of this code for space weather forecasting
by comparing the resulting "synthetic" flux profiles with those of
several real SEP events. References: Lario D., Sanahuja B. and Heras
A.M., 1998, Astrophys. J., 509, 415 Wu S.T., Dryer M., Han S.M., 1983,
Solar Physics, 84, 395
---------------------------------------------------------
Title: Four years of SOHO discoveries - some highlights.
Authors: Fleck, B.; Brekke, P.; Haugan, S.; Duarte, L. S.; Domingo,
V.; Gurman, J. B.; Poland, A. I.
2000ESABu.102...68F Altcode:
Analysis of the helioseismic data from SOHO has shed new light on
solar and heliosheric physics: the structure and dynamics of the
solar interior, the heating and dynamics of the solar corona, and the
acceleration and composition of the solar wind.
---------------------------------------------------------
Title: An Example of Isolated Active Region Energy Evolution: NOAA
AR 7978
Authors: Ortiz, A.; Domingo, V.; Sanahuja, B.; Sánchez, L.
2000ESASP.463..395O Altcode: 2000sctc.proc..395O
The facular contribution to solar irradiance variations on the short
time scale is studied by analysing a simple case of an isolated
active region, NOAA AR7978, during the minimum of 1996. We focus on
the relationship between the temporal evolution of the active region
surface magnetic field, its physical characteristics and the total
facular energy emission, using VIRGO/SOHO and MDI/SOHO data sets.
---------------------------------------------------------
Title: On the Contrast of Faculae and Small Magnetic Features
Authors: Ortiz, A.; Solanki, S. K.; Fligge, M.; Domingo, V.;
Sanahuja, B.
2000ESASP.463..399O Altcode: 2000sctc.proc..399O
Sunspots, faculae and the magnetic network contribute to solar
irradiance variations. The contribution due to faculae and the network
is important for understanding solar irradiance variations, but suffers
from considerable uncertainty. We focus our study on the faculae and
the network which produce an increase in the irradiance. Data from
the Michelson Doppler Interferometer (MDI) are employed. Starting from
the surface distribution of the solar magnetic field we build a mask
to detect bright features and study their contrast dependence on limb
angle and magnetic field. By sorting the magnetic field strength into
different bins we can distinguish between different associated bright
features. We find that the contrast of active region faculae and the
network exhibits different centre to limb variations, implying that
they need to be treated separately when reconstructing variations of
the total solar irradiance.
---------------------------------------------------------
Title: Division XI: Space and High Energy Astrophysics(Astrophysique
Spatiale et Des Hautes Energies)
Authors: Wamsteker, Willem; Baliunas, S.; Brosch, N.; Cesarsky, C.;
Courvoisier, Th. -J. L.; da Costa, J. M.; Domingo, V.; Fransson,
C.; Fabian, A.; Fazio, G.; Hasinger, G.; Inoe, H.; Li, Zhongyuan;
O'Brien, P.; Oertel, G.; Okuda, H.; Quintana, H.; Rangarajan, T. N.;
Schilizzi, R.; Shustov, B.; Thronson, H.; Vilhu, O.; Wang, Zhenru
2000IAUTA..24..357W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of the latitudinal variation of the solar radiance
of non-active regions of the sun.
Authors: Domingo, V.; Sanchez, L.; Appourchaux, T.; Andersen, B.
1998IAUS..185..111D Altcode:
The Luminosity Oscillations Imager (LOI) of the VIRGO experiment
aboard SOHO provides continuous measurement of the solar irradiance
in a 5 nm band around 500 nm. The solar image is broken down in 12
pixels distributed in 4 latitudinal bands. The first year of operation
of the instrument has taken place during a period of solar minimum
activity. The measurements provide an indication of the distribution
of the solar irradiance variations versus latitude. Contributions to
the observed variations due to the presence of active regions are
discussed in relation to the possible effect of the evolving solar
cycle (structure of the convection zone): short term variations versus
long term variations. The problem of the photometric stability of
the measurements needed for the investigation is thoroughly treated
by self consistency and by comparison with other instruments on SOHO
(VIRGO sun- photometers and MDI intensity measurements).
---------------------------------------------------------
Title: Overview of the SOHO Mission
Authors: Domingo, Vicente
1998sers.conf..375D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On the Effect of Active Regions on the Solar Irradiance
Authors: Domingo, V.; Sanchez, L.; Appourchaux, T.; Fröhlich, C.;
Wehrli, C.; Crommelynck, D.; Pap, J.
1997ESASP.415..469D Altcode: 1997cpsh.conf..469D
No abstract at ADS
---------------------------------------------------------
Title: SOHO, its day in the Sun
Authors: Domingo, V.
1997AdSpR..20..581D Altcode:
SOHO, the Solar and Heliospheric Observatory, is a project of
international cooperation between ESA and NASA to study the Sun,
from its deep core to the outer corona, and the solar wind. Three
helioseismology instruments are providing unique data for the study
of the structure and dynamics of the solar interior, from the very
deep core to the outermost layers of the convection zone. A set of
five complementary remote sensing instruments, consisting of EUV,
UV and visible light imagers, spectrographs and coronagraphs, give us
our first comprehensive view of the outer solar atmosphere and corona,
leading to a better understanding of the enigmatic coronal heating and
solar wind acceleration processes. Finally, three experiments complement
the remote sensing observations by making in-situ measurements of
the composition and energy of the solar wind and charged energetic
particles, and another instrument maps the neutral hydrogen in the
heliosphere, and its dynamic change of the Solar Wind. This paper
highlights some of the first results from SOHO.
---------------------------------------------------------
Title: Study of the Effect of Active Regions on the Solar Irradiance
During Solar Minimum
Authors: Domingo, V.; Sanchez, L.; Appourchaux, T.; Froehlich, C.;
Wehrli, C.; Hoeksema, T.; Pap, J.
1997SPD....28.0206D Altcode: 1997BAAS...29..893D
We have determined both the size of the area that contributes to the
solar irradiance increase around an active region and the angular
distribution of the radiance excess in it, using data obtained during
about one year around solar minimum (April 1996 - April 1997). During
the solar minimum and the early raising phase of the new maximum it
is possible to study the effect of isolated active regions while there
are few of them. The result of this study will be important to separate
the contribution of the active regions to the solar irradiance change
during the solar cycle from any underlying long term effect, if there
is one. The solar radiance measured by the Low-resolution Oscillations
Imager (LOI) of the VIRGO instrument and by the MDI instrument aboard
SOHO is used to determine the dimension of the radiating area. The
increase in irradance is determined by the Sun Photometers (SPM)
and Radiometers on the VIRGO instrument.
---------------------------------------------------------
Title: First results from VIRGO on SoHO
Authors: Frohlich, C.; Andersen, B. N.; Appourchaux, T.; Berthomieu,
G.; Crommelynck, D. A.; Domingo, V.; Fichot, A.; Finsterle, W.;
Gómez, M. F.; Gough, D.; Jiménez, A.; Leifsen, T.; Lombaerts, M.;
Pap, J. M.; Provost, J.; Roca Cortés, T.; Romero, J.; Roth, H. -J.;
Sekii, T.; Telljohann, U.; Toutain, T.; Wehrli, C.
1997IAUS..181...67F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Solar and Heliospheric Observatory (SOHO) in 1996.
Authors: Domingo, V.; Fleck, B.; Martens, P.; Sanchez, L.
1997joso.proc....4D Altcode:
This report gives a brief overview of SOHO's scientific production in
its first year of operation.
---------------------------------------------------------
Title: First Results from VIRGO, the Experiment for Helioseismology
and Solar Irradiance Monitoring on SOHO
Authors: Fröhlich, Claus; Andersen, Bo N.; Appourchaux, Thierry;
Berthomieu, Gabrielle; Crommelynck, Dominique A.; Domingo, Vicente;
Fichot, Alain; Finsterle, Wolfgang; Gómez, Maria F.; Gough, Douglas;
Jiménez, Antonio; Leifsen, Torben; Lombaerts, Marc; Pap, Judit M.;
Provost, Janine; Roca Cortés, Teodoro; Romero, José; Roth, Hansjörg;
Sekii, Takashi; Telljohann, Udo; Toutain, Thierry; Wehrli, Christoph
1997SoPh..170....1F Altcode:
First results from the VIRGO experiment (Variability of solar IRradiance
and Gravity Oscillations) on the ESA/NASA Mission SOHO (Solar and
Heliospheric Observatory) are reported. The observations started
mid-January 1996 for the radiometers and sunphotometers and near the
end of March for the luminosity oscillation imager. The performance of
all the instruments is very good, and the time series of the first 4-6
months are evaluated in terms of solar irradiance variability, solar
background noise characteristics and p-mode oscillations. The solar
irradiance is modulated by the passage of active regions across the
disk, but not all of the modulation is straightforwardly explained in
terms of sunspot flux blocking and facular enhancement. Helioseismic
inversions of the observed p-mode frequencies are more-or-less in
agreement with the latest standard solar models. The comparison of
VIRGO results with earlier ones shows evidence that magnetic activity
plays a significant role in the dynamics of the oscillations beyond
its modulation of the resonant frequencies. Moreover, by comparing
the amplitudes of different components ofp -mode multiplets, each of
which are influenced differently by spatial inhomogeneity, we have
found that activity enhances excitation.
---------------------------------------------------------
Title: The first results from SOHO.
Authors: Domingo, V.; Fleck, B.; Poland, A.
1996ESABu..87....7D Altcode:
SOHO, launched by an Atlas II-AS from Cape Canaveral on 2 December 1995,
was inserted into its halo orbit around the L1 Lagrangian point. Typical
examples of the unique results being obtained with SOHO's instruments
are presented.
---------------------------------------------------------
Title: SOLCON Solar Constant Observations from the ATLAS Missions
Authors: Crommelynck, Dominique; Fichot, Alain; Domingo, Vicente;
Lee, Robert, III
1996GeoRL..23.2293C Altcode:
The solar constant observations obtained by the SOLCON/ATLAS
experiment during the three successive missions are presented
based on the Space Absolute Radiometric Reference (SARR) defined
during the ATLAS-2 mission. The objectives of SOLCON, namely to
obtain accurate measurements of the solar constant and to compare
them with the observations obtained from free flyers in the hope of
establishing a baseline and strategy for monitoring the solar constant
at climate scale, have been achieved successfully with the three ATLAS
missions. The long range objective of insuring the solar constant data
continuity will, however, require that an alternative approach than
that of the ATLAS program be found to fly and retrieve SOLCON.
---------------------------------------------------------
Title: The history of thge SOHO mission.
Authors: Huber, M. C. E.; Bonnet, R. M.; Dale, D. C.; Arduini, M.;
Fröhlich, C.; Domingo, V.; Whitcomb, G.
1996ESABu..86...25H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: ESA Report to the : 31 : COSPAR meeting held in Birmingham,
UK July 1996
Authors: Benvenuti, P.; Chicarro, A.; Domingo, V.
1996ertc.book.....B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: VIRGO: Experiment for Helioseismology and Solar Irradiance
Monitoring
Authors: Fröhlich, Claus; Romero, José; Roth, Hansjörg; Wehrli,
Christoph; Andersen, Bo N.; Appourchaux, Thierry; Domingo, Vicente;
Telljohann, Udo; Berthomieu, Gabrielle; Delache, Philippe; Provost,
Janine; Toutain, Thierry; Crommelynck, Dominique A.; Chevalier,
André; Fichot, Alain; Däppen, Werner; Gough, Douglas; Hoeksema,
Todd; Jiménez, Antonio; Gómez, Maria F.; Herreros, José M.; Cortés,
Teodoro Roca; Jones, Andrew R.; Pap, Judit M.; Willson, Richard C.
1995SoPh..162..101F Altcode:
The scientific objective of the VIRGO experiment (Variability of solar
IRradiance and Gravity Oscillations) is to determine the characteristics
of pressure and internal gravity oscillations by observing irradiance
and radiance variations, to measure the solar total and spectral
irradiance and to quantify their variability over periods of days to
the duration of the mission. With these data helioseismological methods
can be used to probe the solar interior. Certain characteristics of
convection and its interaction with magnetic fields, related to, for
example, activity, will be studied from the results of the irradiance
monitoring and from the comparison of amplitudes and phases of the
oscillations as manifest in brightness from VIRGO, in velocity from
GOLF, and in both velocity and continuum intensity from SOI/MDI. The
VIRGO experiment contains two different active-cavity radiometers for
monitoring the solar `constant', two three-channel sunphotometers (SPM)
for the measurement of the spectral irradiance at 402, 500 and 862 nm,
and a low-resolution imager (LOI) with 12 pixels, for the measurement
of the radiance distribution over the solar disk at 500 um. In this
paper the scientific objectives of VIRGO are presented, the instruments
and the data acquisition and control system are described in detail,
and their measured performance is given.
---------------------------------------------------------
Title: Preface
Authors: Fleck, B.; Domingo, V.; Poland, A.
1995SoPh..162D...9F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The SOHO mission.
Authors: Fleck, B.; Domingo, V.; Poland, A. I.
1995SoPh..162.....F Altcode:
SOHO, the Solar and Heliospheric Observatory, is a project of
international cooperation between ESA and NASA to study the Sun, from
its deep core to the outer corona. This special issue is dedicated to
the SOHO payload and to its operation.
---------------------------------------------------------
Title: The SOHO Mission: an Overview
Authors: Domingo, V.; Fleck, B.; Poland, A. I.
1995SoPh..162....1D Altcode:
The Solar and Heliospheric Observatory (SOHO) is a space mission
that forms part of the Solar-Terrestrial Science Program (STSP),
developed in a collaborative effort by the European Space Agency (ESA)
and the National Aeronautics and Space Administration (NASA). The
STSP constitutes the first "cornerstone" of ESA's long-term
programme known as "Space Science — Horizon 2000". The principal
scientific objectives of the SOHO mission are a) to reach a better
understanding of the structure and dynamics of the solar interior
using techniques of helioseismology, and b) to gain better insight
into the physical processes that form and heat the Sun's corona,
maintain it and give rise to its acceleration into the solar wind. To
achieve these goals, SOHO carries a payload consisting of 12 sets of
complementary instruments. SOHO is a three-axis stabilized spacecraft
with a total mass of 1850 kg; 1150 W of power will be provided by
the solar panels. The payload weighs about 640 kg and will consume
450 W in orbit. SOHO will be launched by an ATLAS II-AS and will
be placed in a halo orbit around the Sun-Earth L1 Lagrangian point
where it will be continuously pointing to Sun centre with an accuracy
of 10 arcsec. Pointing stability will be better than 1 arcsec over
15 min intervals. The SOHO payload produces a continuous science
data stream of 40 kbits/s which will be increased by 160 kbits/s
whenever the solar oscillations imaging instrument is operated in its
highrate mode. Telemetry will be received by NASA's Deep Space Network
(DSN). Planning, coordination and operation of the spacecraft and the
scientific payload will be conducted from the Experiment Operations
Facility (EOF) at NASA's Goddard Space Flight Center (GSFC).
---------------------------------------------------------
Title: The SOHO payload and its testing.
Authors: Berner, C.; Domingo, V.
1995ESABu..84...92B Altcode:
The following topics are dealt with: history, science objectives and
payload, the AIV programme.
---------------------------------------------------------
Title: Helioseismology
Authors: Hoeksema, J. T.; Domingo, V.; Fleck, B.; Battrick, Bruce
1995ESASP.376b....H Altcode: 1995help.confP....H
No abstract at ADS
---------------------------------------------------------
Title: SOHO: The Solar and Heliospheric Observatory
Authors: Domingo, V.; Fleck, B.; Poland, A. I.
1995SSRv...72...81D Altcode:
The Solar and Heliospheric Observatory (SOHO), together with the Cluster
mission, constitutes ESA's Solar Terrestrial Science Programme (STSP),
the first “Cornerstone” of the Agency's long-term programme “Space
Science — Horizon 2000”. STSP, which is being developed in a strong
collaborative effort with NASA, will allow comprehensive studies
to be made of the both the Sun's interior and its outer atmosphere,
the acceleration and propagation of the solar wind and its interaction
with the Earth. This paper gives a brief overview of one part of STSP,
the SOHO mission.
---------------------------------------------------------
Title: The SOHO Mission and Helioseismology
Authors: Domingo, V.
1995ESASP.376a...3D Altcode: 1995soho....1....3D; 1995heli.conf....3D
Three of the SOHO scientific instruments are devoted to helioseismology,
and the mission has been designed with specifications that are required
to obtain good oscillations measurements. The three instruments were
selected to complement each other to achieve a comprehensive set of data
to tackle the pending helioseismologic problems that were considered
difficult to solve with ground-based instruments. GOLF (l = 0-3) and
VIRGO (l = 0-7) in the low degree modes area and MDI in the complete
range up to l = 4000 modes. In addition, several instruments of SOHO
investigate, by imaging and spectroscopy, the transition region and
the corona. Three other investigations aboard SOHO study "in situ"
the resulting solar wind and energetic particles.
---------------------------------------------------------
Title: VIRGO - the Solar Monitor Experiment on SOHO
Authors: Appourchaux, T.; Domingo, V.; Frohlich, C.; Romero, J.;
Wehrli, C.; Andersen, B. N.; Berthomieu, G.; Delache, P.; Crommelynck,
D.; Jimenez, A.; Roca Cortes, T.; Jones, A. R.
1995ASPC...76..408A Altcode: 1995gong.conf..408A
No abstract at ADS
---------------------------------------------------------
Title: The SOHO mission
Authors: Fleck, B.; Domingo, V.; Poland, A.
1995somi.book.....F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: SOHO: The Solar and Heliospheric Observatory
Authors: Domingo, V.; Fleck, B.; Poland, A. I.
1995hlh..conf...81D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Helioseismology
Authors: Hoeksema, J. T.; Domingo, V.; Fleck, B.; Battrick, Bruce
1995ESASP.376a....H Altcode: 1995heli.conf.....H
No abstract at ADS
---------------------------------------------------------
Title: The SOHO mission Poland.
Authors: Fleck, B.; Domingo, V.; Poland, Arthur I.
1995sohp.book.....F Altcode: 1995QB521.S5828....
No abstract at ADS
---------------------------------------------------------
Title: Book Review: Solar photo rates for planetary atmospheres and
atmospheric pollutants / Kluwer, 1992
Authors: Domingo, V.; Domingo, V.
1994SoPh..154..401D Altcode: 1994SoPh..154..401H
No abstract at ADS
---------------------------------------------------------
Title: The scientific payload of the space-based Solar and
Heliospheric Observatory (SOHO)
Authors: Domingo, V.; Fleck, B.; Poland, A. I.
1994SSRv...70....7D Altcode:
The space-based Solar and Heliospheric Observatory (SOHO) is a joint
venture of ESA and NASA within the frame of the Solar Terrestrial
Science Programme (STSP), the first “Cornerstone” of ESA's long-term
programme “Space Science — Horizon 2000”. The principal scientific
objectives of the SOHO mission are: a) a better understanding of
the structure and dynamics of the solar interior using techniques of
helioseismology, and b) a better insight into the physical processes
that form and heat the Sun's corona, maintain it and give rise to
its acceleration into the solar wind. To achieve these goals, SOHO
carries a payload consisting of 12 sets of complementary instruments
which are briefly described here.
---------------------------------------------------------
Title: SOHO operations and ground system
Authors: Poland, A. I.; Domingo, V.; Fleck, B.
1994SSRv...70...13P Altcode:
SOHO is a joint ESA/NASA mission to study the sun from its interior to,
and including, the solar wind in interplanetary space. It is currently
scheduled for launch in 1995. After launch SOHO with be operated from
the Experiment Operations Facility (EOF) at Goddard Space Flight Center
(GSFC). The EOF will consist of facilities for instrument commanding,
data reception, data reduction and data analysis. In this paper the
operations concepts including instrument ground commanding from the EOF
and communications capabilities between the EOF and ground observatories
and the public networks in general will be described.
---------------------------------------------------------
Title: Preliminary results of solar constant observations with the
SOLCON experiment on ATLAS-1
Authors: Crommelynck, D.; Domingo, V.; Barkstrom, B.; Lee, R. B.;
Donaldson, J.; Telljohann, U.; Warren, L.; Fichot, A.
1994AdSpR..14i.253C Altcode: 1994AdSpR..14..253C
A brief description is given of the SOLCON experiment on ATLAS 1,
its scientific and technical objectives, as well as its measurement
principle and its on board chronology of operations. A preliminary
value of the solar constant during the third solar operation of the
mission is also provided.
---------------------------------------------------------
Title: Summary of Future Space Observations at Different Wavelengths
Authors: Domingo, V.
1994svsp.coll..101D Altcode: 1994IAUCo.143P.101D
No abstract at ADS
---------------------------------------------------------
Title: Total Solar Irradiance Observations from the EURECA and
ATLAS Experiments
Authors: Crommelynck, D.; Domingo, V.; Fichot, A.; Lee, B.
1994svsp.coll...63C Altcode: 1994IAUCo.143P..63C
No abstract at ADS
---------------------------------------------------------
Title: SOHO Science Opportunities
Authors: Fleck, B.; Domingo, V.; Poland, A. I.
1994scs..conf..609F Altcode: 1994IAUCo.144..609F
The principal scientific objectives of the SOHO mission are: a)
a better understanding of the structure and dynamics of the solar
interior using techniques of helioseismology, and b) a better insight
into the physical processes that form and heat the Sun's corona,
maintain it and give rise to its acceleration into the solar wind. To
achieve these goals, SOHO carries a payload consisting of 12 sets of
complementary instruments which are briefly described here.
---------------------------------------------------------
Title: SOHO Operations
Authors: Fleck, B.; Domingo, V.; Poland, A. I.
1994scs..conf..614F Altcode: 1994IAUCo.144..614F
SOHO, the Solar and Heliospheric Observatory, is currently scheduled
for launch in 1995. After launch SOHO will be operated from the
Experiment Operations Faciliy (EOF) at Goddard Space Flight Center
(GSFC). The EOF will consist of facilities for instrument commanding,
data reception, data reduction and data analysis. This paper briefly
describes the operations concepts.
---------------------------------------------------------
Title: SOHO - The Solar and Heliospheric Observatory
Authors: Fleck, B.; Domingo, V.
1994smf..conf..408F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: SOHO: science objectives and capabilities
Authors: Fleck, B.; Domingo, V.; Poland, A. I.
1994ASIC..433..517F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Invited Talk: (SOHO Operations and Coordination with
Ground-based Observatories)
Authors: Domingo, V.; Fleck, B.
1993BAAS...25.1195D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Some European activities in support of the SOHO mission.
Authors: Huber, Martin C. E.; Domingo, Vicente
1992ESASP.348..393H Altcode: 1992cscl.work..393H
The rationale and potential functions of the European Science Data
and Operations Centre (ESDOC) are outlined. Other efforts, namely
the gathering of support - through the Joint Organisation for Solar
Observations (JOSO) - for ground-based observations in the context of
the SOHO mission, as well as the development of a vacuum-ultraviolet
(VUV) transfer source standard - to be used for radiometrically
intercomparing spectrometric SOHO instruments - are also described.
---------------------------------------------------------
Title: ESA's report to the 29th COSPAR Meeting
Authors: Appourchaux, T.; Chicarro, A.; Domingo, V.; Fridlund, M.;
Huber, M.; Innocenti, L.; Jakobsen, P.; Kessler, M.; Lebreton, J. P.;
Parmar, A.
1992wadc.meet.....A Altcode:
All ESA missions in operation, under development, or in planning are
described. Missions beyond the operational phase are also presented
if considerable effort is still being expended in supporting the data
analysis through an archive. The aging and completed missions are:
IUE, Exosat, Hipparcos, Giotto extended mission, Ulysses, and Hubble
Space Telescope. The projects under development are: Infrared Space
Observatory (ISO), the Solar Terrestrial Science Program (STSP) (which
comprises the four Cluster spacecraft and the Solar and Heliospheric
Observatory (SOHO)), the X-ray Multimirror Mission (XMM) and the
Cassini/Huygens mission. Missions under study are: the Far Infrared
Space Telescope (FIRST), the comet nucleus sample return (Rosetta),
the International Gamma Ray Laboratory (INTEGRAL), a network of three
semi hard landers to be placed on the Martian surface (MARSNET), a
mission for probing the interior and rotation of stars (PRISMA), and
a Satellite Test of the Equivalence Principle (STEP). Missions beyond
Horizon 2000 are: Return to the Moon, interferometry from space, and
Vulcan. ESA platforms described are Eureca (the European retrieval
carrier) and Simuris (a solar system and stellar interferometric
mission for ultrahigh resolution imaging and spectroscopy).
---------------------------------------------------------
Title: SOHO and Cluster. Solar and geospheric plasmas and solar
structure.
Authors: Domingo, V.; Schmidt, R.
1991EN.....22..213D Altcode:
The SOHO/Cluster satellite missions will provide an unique opportunity
to advance our understanding of the physics of the solar-terrestrial
system.
---------------------------------------------------------
Title: Three Solar Filament Disappearances Associated with
Interplanetary Low Energy Particle Events
Authors: Sanahuja, B.; Heras, A. M.; Domingo, V.; Joselyn, J. A.
1991SoPh..134..379S Altcode:
Three low-energy particle events (35-1600 keV) associated with
interplanetary shocks, detected at 1 AU by ISEE-3, have been
identified as originating in solar disappearing filaments instead
of large flares. This increases to fourteen the number of events
of this kind presently known. The observational characteristics of
these non-flare generated events are similar to the ones of the other
eleven events already known (i.e., absence of type II or IV bursts,
weak X-ray emission, Hα brightening in the surroundings of the
filament disappearance, frequent presence of a double-ribbon event,
slow propagation of the generated interplanetary shock, lack of shock
deceleration).
---------------------------------------------------------
Title: The SOHO Space Satellite: UV instrumentation.
Authors: Poland, Arthur I.; Domingo, Vicente
1991SPIE.1343..310P Altcode:
The solar and heliospheric observatory, SOHO will be placed into a halo
orbit around the L1 sun-earth Lagrangian point in 1995. The authors
describe the ultra-violet and EUV instruments designed to study
the solar atmosphere from the chromosphere through the corona. The
instruments and their basic characteristics are: 1) SUMER - a normal
incidence telescope with a normal incidence spherical concave grating
for stigmatic imaging to measure line profiles and images in the
wavelength range from 500 Å to 1600 Å with a 1.5″resolution; 2) CDS
- a grazing incidence telescope with one grazing incidence astigmatic
spectrograph and one normal incidence toroidal grating spectrograph
to measure line ratios and images in the range from 170 Å to 800
Å with a 2″resolution; 3) EIT - a normal incidence multilayered
telescope to produce narrow band pass images in the spectral lines at
171 Å, 195 Å, 284 Å, and 304 Å with a 3″resolution; 4) UVCS - a
normal incidence coronagraph with a normal incidence toroidal grating
spectrograph to measure line profiles and images of several EUV lines
from ≡500 Å to ≡1200 Å with a several arcsecond resolution;
and 5) SWAN - a lens with hydrogen absorption cell and interference
filter to measure Ly-α profiles in the far corona and heliosphere.
---------------------------------------------------------
Title: The helioseismology experiment on the Phobos planetary
mission. Preliminary results
Authors: Frohlich, C.; Bonnet, R. M.; Bruns, A. V.; Vial, J. C.;
Delaboudiniere, J. P.; Domingo, V.; Kollath, Z.; Kotov, V. A.;
Rachkovskii, D. N.; Wehrli, Ch.; Toulain, T.; Shumko, S. M.
1991BCrAO..83...18F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Solar Variations (SOVA) experiment in the EURECA space
platform
Authors: Crommelynck, D.; Domingo, V.; Fröhlich, C.
1991AdSpR..11d..83C Altcode: 1991AdSpR..11Q..83C
The Solar Variations (SOVA) experiment aboard EURECA will measure the
total and spectral irradiance of the Sun, and their variations. Aims
of the experiment are: - to study the short term (hours to months)
variations of the solar irradiance for the investigation of the
mechanisms of energy redistribution in the convection zone, - to study
periodic fluctuations, with periods between a few minutes and several
hours, for helioseismology and, - to measure the absolute value of the
solar constant to determine its long term variations when compared
with previous and future measurements. Two absolute active cavity
radiometers of different design will measure independently the value
of the total solar irradiance, one relative radiometer will measure
the variations of the total solar irradiance and five photometers
will measure the variations of the spectral irradiance in 5-nm wide
wavelength bands centred at 335, 480, 500, 546 and 865 nm. The European
Retrievable Carrier (Eureca), is an ESA space platform that will be
placed in orbit around the Earth by the NASA Shuttle in October 1991,
and will be recovered after 6 months of operation.
---------------------------------------------------------
Title: Phase difference between irradiance and velocity in low degree
solar p-modes
Authors: Schrijver, C. J.; Jiménez, A.; Domingo, V.; Fröhlich, C.
1991AdSpR..11d..77S Altcode: 1991AdSpR..11Q..77S
We derive phase differences between irradiance and full-disk velocity
variations for l=0, 1, and 2 modes with order ranging from 11 up to 30
(1.8-4.3mHz). We use irradiance measurements from the IPHIR instrument
flown on the PHOBOS mission to Mars during the second half of 1988,
and simultaneous velocity measurements obtained at Tenerife. The
IPHIR instrument measures broad-band irradiance fluctuations and the
derived phase differences are therefore typical of the deep layers of
the photosphere. We select three one week intervals from the 155 day
observing interval of PHOBOS 2 for which simultaneous good quality
velocity data are available. We find a smooth variation of the phase
difference between irradiance at 500nm (5nm FWHM) and velocity from
about 70° at 1.8mHz to 145° at 2.5mHz, while it remains roughly
constant at 145° degrees up to at least 3.5mHz, and possibly up to
4.3mHz. We also show that the phase differences between the green
(500nm) and red (865nm) channels does not differ significantly from
zero below 3mHz, while a small difference of about 10° may exist at
higher frequencies.
---------------------------------------------------------
Title: The helioseismological experiment at the Phobos interplanetary
station - Preliminary results
Authors: Froehlich, C.; Bonnet, R. M.; Bruns, A. V.; Vial, J. C.;
Delaboudiniere, J. P.; Domingo, V.; Kollath, Z.; Kotov, V. A.;
Rachkovskii, D. N.; Wehrli, Ch.
1991IzKry..83...22F Altcode:
Preliminary results obtained from IPHIR (Interplanetary Helioseismology
by Irradiance Measurements), a solar irradiance experiment on board
the Soviet planetary mission Phobos-2, are presented. During the
spacecraft's flight to Mars, the instrument gathered valuable data on
tiny variations of solar irradiance over the course of six months. The
data clearly show 5-min oscillations with relative amplitudes of about
10 exp -5 and with a well-defined pattern of discrete peaks in the
power spectrum. The data of the red channel (it exhibited the lowest
degradation of sensitivity over time) reveal remarkable temporal changes
of amplitudes of discrete peaks within a period range of about 5 min,
but with excellent frequency stability.
---------------------------------------------------------
Title: Desapariciones de filamentos solares como origen de sucesos
de particulas y de los choques interplanetarios asociados.
Authors: Heras, A. M.; Sanahuja, B.; Domingo, V.
1991BAOM...12...12H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: ESA's report to the 28th COSPAR meeting
Authors: Chicarro, A.; Domingo, V.; Frisk, U. O.; Jakobsen, P.;
Knott, K.; Kessler, M. F.; Lebreton, J. P.; Marsden, R.; Peacock,
A.; Perryman, M. A. C.
1990STIN...9030141C Altcode:
Ongoing and complete missions, including IUE, EXOSAT, Hipparcos and
Giotto, are discussed. Projects under development, including Ulysses,
Hubble Space Telescope, ISO (Infrared Space Observatory), the Solar
Terrestrial Science Programme (STSP), Cassini/Huygens and the high
throughput X ray spectroscopy mission (XMM), are reported. Missions
under study are reviewed; the submillimeter spectroscopy mission
(FIRST); Rosetta CNSR (Comet Nucleus Sample Return); third millenium
Mars exploration, interferometry from space and Vulcan missions. The
Eureca A and Columbus Polar Platforms are included.
---------------------------------------------------------
Title: Phase Differences Between Luminosity and Velocity Measurements
of the Acoustic Modes
Authors: Jiménez, A.; Álvarez, M.; Andersen, N. B.; Domingo, V.;
Jones, A.; Pallé, P. L.; Roca Cortés, T.
1990SoPh..126....1J Altcode:
With two photometric stations (Tenerife and Baja California)
the luminosity p-mode spectrum at different wavelengths has been
identified. After a coherence analysis between data from both stations
to verify the solar origin of the peaks identified in luminosity, a
comparative study with simultaneous velocity measurements (obtained at
Tenerife only) has also been made. As a result the frequency dependence
of the phase difference between luminosity and velocity p-modes has been
obtained that is interpreted in terms of a nonadiabatic behaviour of the
solar atmosphere. The amplitude ratios between luminosity and velocity
p-modes have also been obtained. All these results are compared with
theoretical expectations.
---------------------------------------------------------
Title: SOHO - an Observatory to Study the Solar Interior and the
Solar Atmosphere
Authors: Poland, A. I.; Domingo, V.
1990ASSL..166..277P Altcode: 1990oeob.coll..277P; 1990IAUCo.123..277P
The Solar and Heliospheric Observatory (SOHO) is described. The two
main objectives of SOHO are to improve understanding of solar coronal
phenomena and to study solar structure and interior dynamics from
its core to the photosphere. The primary goals of the coronal and
solar wind studies are to understand the coronal heating mechanism
and its expansion into the solar wind. These goals will be achieved
both by remote sensing of the solar atmosphere with high resolution
spectrometers and telescopes and by in situ measurement of the
composition and energy of the resulting solar wind and the energetic
particles that propagate through it. The structure and interior dynamics
are to be studied by helioseismological methods and the measurement
of solar irradiance variations. The SOHO spacecraft will be three-axis
stabilized and located in a halo orbit around the L1 Lagrangian point
(approximately 1 percent of the distance from the Earth to the Sun). It
is currently scheduled for launch in July 1995.
---------------------------------------------------------
Title: The Soho Project and Helioseismology
Authors: Domingo, Vicente
1990LNP...367..257D Altcode: 1990psss.conf..257D
The Solar and heliospheric observatory (Soho) space mission being
developed by ESA and NASA will carry together with other instruments
devoted to the study of the solar atmosphere and solar wind, a set
of instruments that will provide a comprehensive set of measurements
of solar oscillations. Two investigations in Soho aim primarily at the
study of g-modes and low l p-modes and a third one will have the central
interest in high degree oscillations while aiming to extend the validity
of its measurements to low 1 modes overlapping with the other two
investigations. The Soho mission is being designed having into account
the needs of the helioseismology experiments and therefore should be
able to provide the best possible infrastructure for the production
of good quality data. For the data analysis the three experiments
will coordinate their operation and the data handling. It is expected
that Soho will greatly profit of the experience gained with GONG, as
a large fraction of the co-investigators in the Soho helioseismology
investigations form part of the GONG project. The investigations in
Soho have finished the definition phase of their instruments and
the contractor selected by ESA has started on 1 December 1989 the
industrial Phase B, or design phase, of the spacecraft and mission
for a launch in March 1995.
---------------------------------------------------------
Title: Retrieval from Earth Orbit of the Ultra Heavy Cosmic Ray
Experiment on the LDEF Spacecraft
Authors: Thompson, A.; O'Sullivan, D.; Wenzel, K. -P.; Domingo, V.;
Domingo, C.; Daly, J.; Smit, A.
1990ICRC....4..441T Altcode: 1990ICRC...21d.441T; 1989ICRC....4..441T
No abstract at ADS
---------------------------------------------------------
Title: Energetic particles, interplanetary shocks and solar activity
Authors: Domingo, V.; Sanahuja, B.; Heras, A. M.
1989AdSpR...9d.191D Altcode: 1989AdSpR...9..191D
The study of the flow-pattern of energetic protons (35-1600 keV)
associated with interplanetary shocks observed by ISEE-3, is analyzed
as a function of the relative position of the spacecraft with respect
to the shock and to the solar activity that has triggered the events,
and is complemented with a statistical study on the thickness
of bidirectional particle regimes associated with interplanetary
shocks. The result indicates that the region behind the shock where the
driver would be located extends over a wide angle around the longitude
of the triggering event, with little asymmetry with respect to the
propagation direction.
---------------------------------------------------------
Title: Solar Luminosity Oscillation Telescope (SLOT).
Authors: Andersen, Bo Nyborg; Domingo, V.; Jones, A. R.; Korzennik,
Sylvain G.; Jimenez, A.; Palle, Pere L.; Regulo, C.; Roca Cortés,
Teodoro
1988ESASP.286..175A Altcode: 1988ssls.rept..175A
Low degree l = 0-2 solar p-modes have been detected with the
SLOT instruments at Izaña and Baja California. The main source
of noise for these ground based observations is in the terrestrial
atmosphere. However, the data acquisition system still has to have very
slow intrinsic noise. The authors describe how this is achieved in the
SLOT instruments. They also give a general description of the design
and operating principles of the photometers and data acquisition system.
---------------------------------------------------------
Title: VIRGO: The solar monitor experiment on SOHO.
Authors: Froehlich, C.; Andersen, Bo Nyborg; Berthomieu, G.;
Crommelynck, D.; Delache, Philippe; Domingo, V.; Jimenez, A.; Jones,
A. R.; Roca Cortés, Teodoro; Wehrli, Ch.
1988ESASP.286..371F Altcode: 1988ssls.rept..371F
The VIRGO Experiment (Variability of solar Irradiance and Gravity
Oscillations) contains two types of active cavity radiometers for
monitoring of the solar "constant", two three channel sunphotometers
(SPM) for the measurement of spectral irradiance at 335, 500 and 865 nm
and a low resolution imager (LOI) with 12 pixels. The main scientific
objective is probing the solar interior by helioseismology with p-
and g-mode solar oscillations determined from spectral irradiance
(SPM) and radiance (LOI) variations on time scales of minutes to
the mission time. Moreover, the measurements of the variability of
the solar "constant" and spectral irradiance over periods of days to
the mission time will yield information about the convection zone, as
will the comparison of the amplitudes and phases of the oscillations
as manifested in irradiance and radiance (from VIRGO) and velocity
(from GOLF and SOI).
---------------------------------------------------------
Title: Soho status.
Authors: Domingo, V.
1988ESASP.286..363D Altcode: 1988ssls.rept..363D
The scientific payload for Solar and Heliospheric Observatory (Soho)
space mission has been selected. Soho will study the structure of
the solar interior, the physics of the solar corona and the origin of
the solar wind. The spacecraft definition phase will start in October
1989. The launch is expected for March 1995.
---------------------------------------------------------
Title: Solar luminosity oscillations from two stations and correlation
with velocity measurements.
Authors: Jimenez, A.; Palle, Pere L.; Roca Cortés, Teodoro; Andersen,
N. B.; Domingo, V.; Jones, A. R.; Alvarez, M.; Ledezma, E.
1988ESASP.286..163J Altcode: 1988ssls.rept..163J
Since 1984 the measurements of a quadrupole photometer sites at the
Observatorio del Teide (Izaña, Tenerife) have made it possible to
identify the p-mode luminosity spectrum with simultaneous velocity
observations. Comparing this data, the adiabatic behaviour of solar
atmosphere and theoretical expectations from solar models have been
tested. Now, in order to increase the signal-to-noise ratio and reduce
the sidebands due to the night-time data gaps, a second identical
photometer was set-up in December 1987, at the Observatorio de San
Pedro Mártir (Baja California Norte, Mexico). The first results of
the observations of these two stations are analyzed and compared with
simultaneous velocity measurements.
---------------------------------------------------------
Title: IPHIR: The helioseismology experiment on the PHOBOS mission.
Authors: Fröhlich, C.; Bonnet, R. M.; Bruns, A. V.; Delaboudinière,
J. P.; Domingo, V.; Kotov, V. A.; Kollath, Z.; Rashkovsky, D. N.;
Toutain, T.; Vial, J. C.; Wehrli, C.
1988ESASP.286..359F Altcode: 1988ssls.rept..359F
IPHIR (InterPlanetary Helioseismology by IRradiance measurements) is
a solar irradiance experiment on the USSR planetary mission PHOBOS to
Mars and its satellite Phobos. The experiment is a cooperative effort
of PMOD/WRC, LPSP, SSD/ESA, KrAO and CRIP. The sensor is a three channel
sunphotometer (SPM) which measures the solar spectral irradiance at 335,
500 and 865 nm with a precision of better than 1 ppm. A two axis solar
sensor (TASS) is added to monitor the moderate solar pointing of the
spacecraft. A microprocessor based data processing unit controls the
sensor operation, acquires the data, and performs the data compression
for the transmission at a mean rate of 1 bit/s. The two spacecrafts
have been launched on July 7th and 12th, 1988. The experiment on
PHOBOS I gathered data during 45 days before the S/C was lost, the
one on PHOBOS II is still operating. The data recovery is excellent
with virtually 100% coverage. Although the signal is disturbed by the
pointing of the spacecraft the results of a preliminary analysis in
the range of the 5-minutes oscillations demonstrate the improvement
achievable due to the fact that the time series is truly continuous
and the instrumental and sampling noise is very low.
---------------------------------------------------------
Title: Luminosity Oscillations Imager (LOI).
Authors: Andersen, Bo Nyborg; Domingo, V.; Jones, A. R.; Jimenez,
A.; Palle, Pere L.; Regulo, C.; Roca Cortés, Teodoro
1988ESASP.286..385A Altcode: 1988ssls.rept..385A
The VIRGO (Variability in Irradiance and Gravity Oscillations)
investigation has been selected to fly on ESA's SOHO mission. One of
the components of the VIRGO is a small imaging solar photometer. This
instrument, the Luminosity Oscillations Imager (LOI), will observe
the solar radiance with 12 pixels resolution. A prototype of the LOI
has been developed at ESTEC. This prototype was built mainly to test
possible detector configurations, the data acquisition system and the
internal guider. The prototype has been operating at Izaña, Tenerife
since April this year.
---------------------------------------------------------
Title: SOHO: an observatory to study the solar interior and the
solar atmosphere
Authors: Domingo, V.; Poland, A. I.
1988sohi.rept....7D Altcode:
The Solar and Heliospheric Observatory (SOHO) is described. The two
main objectives of SOHO are to improve understanding of solar coronal
phenomena and to study solar structure and interior dynamics from
its core to the photosphere. The primary goals of the coronal and
solar wind studies are to understand the coronal heating mechanism
and its expansion into the solar wind. These goals will be achieved
both by remote sensing of the solar atmosphere with high resolution
spectrometers and telescopes and by in situ measurement of the
composition and energy of the resulting solar wind and the energetic
particles that propagate through it. The structure and interior dynamics
are to be studied by helioseismological methods and the measurement
of solar irradiance variations. The SOHO spacecraft will be three-axis
stabilized and located in a halo orbit around the L1 Lagrangian point
(approximately 1 percent of the distance from the Earth to the Sun). It
is currently scheduled for launch in July 1995.
---------------------------------------------------------
Title: VIRGO: The solar monitor experiment on SOHO
Authors: Froehlich, C.; Andersen, B. N.; Berthomieu, G.; Crommelynck,
D.; Delache, Ph.; Domingo, V.; Jimenez, A.; Jones, A. R.; Roca Cortes,
T.; Wehrli, Ch.
1988sohi.rept...19F Altcode:
The Variability of solar IRradiance and Gravity Oscillations (VIRGO)
experiment contains two types of active cavity radiometers for
monitoring of the solar constant, two three channel sunphotometers for
the measurement of spectral irradiance at 335, 500 and 865 nm and a
low resolution imager with 12 pixels. The main scientific objective
is probing the solar interior by helioseismology with p and g mode
solar oscillations determined from spectral irradiance and radiance
variations on time scales of minutes to the mission time. Information
about the convection zone is thus obtained. The comparison of the
amplitudes and phases of the oscillations as manifested in irradiance
and radiance (from VIRGO) and velocity as measured by the GOLF (global
oscillations at low frequencies) experiment are also used in analyzing
the convection zone.
---------------------------------------------------------
Title: Diurnal photometric conditions at Teide observatory and
long-term solar irradiance variations
Authors: Andersen, B.; Domingo, V.; Jiménez, A.; Jones, A.; Korzennik,
S.; Pallé, P. L.; Pérez Hernández, F.; Régulo, C.; Roca Cortés,
T.; Tomás, L. L.
1988SoPh..116..391A Altcode:
Monochromatic extinction coefficients at four wavelengths have been
obtained over a period of more than two years at the Observatorio del
Teide (Izaña Tenerife) using a full disc, direct sunlight, quadruple
photometer devoted to the detection of integral luminosity oscillations
of the Sun. The mean extinction coefficients (0.13 at 500 nm) show
a seasonal variation of about 15%, the best atmospheric conditions
being in winter and autumn. Moreover, in anyone day the extinction
coefficient in the afternoon is always lower than the one in the
morning by ∼ 7%. A one-year period fluctuation, with an amplitude
of ∼ 0.035 mag, has been identified in the instrumental magnitudes
outside the atmosphere, and is interpreted as the variation produced
by the different Sun-Earth distance from winter to summer. Finally,
the study made to detect periodic time fluctuations in both, Sun's
magnitude and extinction coefficients, has given null results at levels
of ∼ 0.04 and ∼ 1.8%, respectively.
---------------------------------------------------------
Title: ESA report to the 27th COSPAR meeting
Authors: Domingo, V.; Fisk, U. O.; Grard, R.; Jakobsen, P.; Kessler,
M. F.; Lebreton, J. -P.; Marsden, R.; Peacock, A.; Pedersen, A.;
Perryman, M. A. C.
1988STIN...8830556D Altcode:
The ISEE, IUE, EXOSAT, and Giotto missions are described. The
status of the Ulysses, Hubble Space Telescope, HIPPARCOS, ISO, and
solar-terrestrial science programs is discussed. The high throughput
X-ray spectroscopy mission, submillimeter spectroscopy mission, and the
comet nucleus sample return mission are presented. The CASSINI, GRASP,
Lyman, Quasat, Vesta, and Giotto extended missions are introduced. The
EURECA and Columbus space station programs are reviewed.
---------------------------------------------------------
Title: Low-energy particle events generated by solar disappearing
filaments
Authors: Heras, A. M.; Sanahuja, B.; Domingo, V.; Joselyn, J. A.
1988A&A...197..297H Altcode:
Five large low-energy (E less than 2 MeV) proton events associated
with interplanetary shocks, observed at 1 AU by the ISEE-3 probe,
appeared to be triggered by solar disappearing filaments instead of
solar flare activity. These events will join the other six events of
this kind already known. In this paper these events are identified and
a comparative study of the interplanetary proton for the nonflare and
flaring situations is provided. Proton events that are triggered by
disappearing filaments appears not to be associated with the strong
X-ray or radio radiation that characterizes solar flares.
---------------------------------------------------------
Title: Diffuse Gamma Rays with Energies Greater than 1 X 10 14 eV
Observed in the Southern Hemisphere
Authors: Suga, K.; Toyoda, Y.; Kamata, K.; Murakami, K.; Lapointe,
M.; Gaebler, J.; Escobar, I.; Saavedra, O.; Domingo, V.; Shibata,
S.; Akiyama, H.; Takano, M.; Uchino, K.
1988ApJ...326.1036S Altcode:
The data of extensive air showers with a low content of muons and
hadrons, observed in the period 1964-1966 at Mount Chacaltaya in
Bolivia, have been reanalyzed. Arrival directions of those showers
selected so as to favor small initiation depths in the atmosphere (to
enhance the contribution from gamma-ray-initiated showers) reveal a
3.8 sigma peak above an expected background from the region of alpha
= 180-210 deg in the band of delta = 0 to -40 deg. The integral flux
of diffuse gamma-rays above 1 x 10 to the 14th eV estimated from this
excess is about 6.0 x 10 to the -12th/sq cm per sec per sr. In order
to explain this very high flux, the possible contribution of gamma-rays
from Loop 1 as well as the inverse Compton photons produced in the 2.7
K photon background as progeny of gamma-rays from Cyg X-3-like sources.
---------------------------------------------------------
Title: Cluster and SOHO: A joint endeavor by ESA and NASA to address
problems in solar, heliospheric, and space plasma physics
Authors: Schmidt, Rudolf; Domingo, Vicente; Shawhan, Stanley D.;
Bohlin, David
1988EOSTr..69..177S Altcode:
The NASA/ESA Solar-Terrestrial Science Program, which consists of
the four-spacecraft cluster mission and the Solar and Heliospheric
Observatory (SOHO), is examined. It is expected that the SOHO spacecraft
will be launched in 1995 to study solar interior structure and the
physical processes associated with the solar corona. The SOHO design,
operation, data, and ground segment are discussed. The Cluster mission
is designed to study small-scale structures in the earth's plasma
environment. The Soviet Union is expected to contribute two additional
spacecraft, which will be similar to Cluster in instrumentation and
design. The capabilities, mission strategy, spacecraft design, payload,
and ground segment of Cluster are discussed.
---------------------------------------------------------
Title: Correlation between velocity and luminosity measurements of
solar oscillations
Authors: Jimenez, A.; Palle, P. L.; Roca Cortes, T.; Domingo, V.
1988A&A...193..298J Altcode:
Following the work started in 1984 to detect the solar intensity
oscillations from ground (Jimenez et al., 1986), simultaneous
velocity and intensity observations of 16 contiguous days of very high
atmospheric quality obtained at Izana (Tenerife) have been analyzed. The
frequencies of the p-mode intensity spectrum at three channels
(500, 680 and 870 nm) and those of the velocity spectrum have been
obtained. Amplitude ratios in the intensity measurements give results
of 1.6 and 2.2 when comparing the last two channels with the first one,
and their relative phases give a null result at any frequency in the
5 minute range. The relative phases between luminosity and intensity
measurements give a mean result of -120 degrees. Finally, the ratio
of the amplitudes of the intensity oscillations to the velocity ones
correlates very well with theoretical expectations and it yields a
fractional variation of the effective temperature of 2 x 10 to the -6th.
---------------------------------------------------------
Title: Groundbased Observations of Solar Luminosity Oscillations
Authors: Andersen, B. N.; Domingo, V.
1988IAUS..123...67A Altcode:
Results from ground based observations of low degree solar luminosity
variations are presented. By using data from up to 15 consecutive
excellent days the majority of the l = 0, 1 and 2 peaks in the region
2.5 - 3.5 mHz may marginally be identified.
---------------------------------------------------------
Title: The SOHO project: helioseismology investigations
Authors: Domingo, V.; Poland, A.
1988AdSpR...8k.109D Altcode: 1988AdSpR...8..109D
The solar and heliospheric observatory, Soho, will be placed into a
halo orbit around the L1 Sun-Earth Lagrangian point in 1995. It will
carry a set of instruments to study the physical phenomena in the
solar atmosphere that heat the solar corona, the mechanisms by which
the solar corona expands into the solar wind, and investigate the
structure of the solar interior by the study of solar oscillations,
both in velocity and in intensity (Helioseismology). <P />In this paper
we describe the mission and the investigations to be carried out with
the helioseismology instruments in the payload. A solar oscillations
imager will measure velocity oscillations of degree up to 4000, while
two other instruments will measure very long series of low degree modes
of oscillation, one of them in velocity and the other in irradiance. The
data obtained will be used to study the radial stratification and the
longitudinal variation of the physical characteristics of the Sun,
as well as many dynamical phenomena of the upper layers of the solar
atmosphere.
---------------------------------------------------------
Title: Earthbased Observations of Solar Luminosity Oscillations
Authors: Jimenez, A.; Palle, P. L.; Perez-Hernandez, F.; Regulo, C.;
Roca-Cortes, T.; Domingo, V.; Korzennik, S.
1988IAUS..123...71J Altcode:
Earth based multichannel photometry of integral sunlight has been
obtained at Izaña (Tenerife) during 1984 - 1986. Power spectra of the
solar luminosity variations of individual days show power in the 5
minute interval above noise at a level comparable to SMM data. When
combining contigous days of data the signature of p mode solar
oscillations spectrum appears, although individual peak identification
is difficult.
---------------------------------------------------------
Title: Helioseismology from Space - the SOHO Project
Authors: Domingo, V.
1988IAUS..123..545D Altcode:
The Solar and Heliospheric Observatory (SOHO) has been proposed with
the following aims: To investigate and understand the physical processes
that form the solar corona, maintain it and give rise to the expanding
solar wind, by high resolution spectroscopy of the chromosphere,
transition region and corona in combination with "in situ" study of the
resulting solar wind streams and associated fields; to investigate the
solar interior structure by methods of helioseismology. It is foreseen
that the spacecraft will be launched by the end of 1994.
---------------------------------------------------------
Title: Current Understanding and Issues on Electron Beam Injection
in Space
Authors: Poland, A. I.; Domingo, V.
1988AdSpR...8k.101P Altcode: 1988AdSpR...8Q.101P
The Solar and Heliospheric Observatory (SOHO) satellite mission is
planned to study the solar interior, to investigate the physical
phenomena related to the formation of the solar corona and the solar
wind, and to make in situ measurements of the solar wind. The SOHO
instruments designed to study the solar atmosphere and the solar wind
are described. The experiments include the study of solar UV radiation,
a coronal diagnostic spectrometer, an extreme UV imaging telescope, a UV
coronagraph spectrometer, a white light and spectrometric coronagraph,
and a study of solar wind anisotropies.
---------------------------------------------------------
Title: Soho and Cluster - the scientific instruments.
Authors: Domingo, V.; Schmidt, R.; Poland, A. I.; Goldstein, M. L.
1988ESABu..56...24D Altcode:
The need to understand the complex processes that control the structure
and dynamics of our daylight star and define the Earth's environment
in space, has long been widely realised. Its continuing importance is
reflected by the fact that twenty-three Principal Investigators and
several hundred Co-Investigators from more than eighteen countries
are now actively involved in the preparations for and execution of
the Soho and Cluster missions.
---------------------------------------------------------
Title: Low-energy protons associated with interplanetary shocks as
a coherent population
Authors: Sanahuja, B.; Domingo, V.
1987JGR....92.7280S Altcode:
We investigate the flow pattern of low-energy protons (35-1600 keV)
associated with interplanetary shocks observed by ISEE-3 between August
1978 and April 1980. The analysis of the shape of the distribution
function in the solar wind frame and its temporal evolution indicates
that the low-energy protons can behave as a coherent, independent
population of particles in the solar wind. Ahead of the shock this
population propagates along the magnetic field in the same direction as
the solar wind flow, while after the passage of the perturbed region
associated with the shock, it propagates in the opposite sense. The
behavior of the flow pattern of this population through the shock
front is discussed for the 17 largest events observed in this period.
---------------------------------------------------------
Title: Extended Exposure for the Ultra Heavy Cosmic Ray Experiment
on the LDEF Spacecraft
Authors: Thompson, A.; O'Sullivan, D.; Domingo, C.; Wenzel, K. -P.;
Domingo, V.
1987ICRC....2..402T Altcode: 1987ICRC...20b.402T; 1987ICRC....2..402D
No abstract at ADS
---------------------------------------------------------
Title: UHE gamma-rays from Vela X-1 and Cen X-3.
Authors: Suga, K.; Toyoda, Y.; Kamata, K.; Murakami, K.; Lapointe,
M.; Gaebler, J.; Escobar, I.; Saavedra, O.; Domingo, V.; Shibata,
S.; Akiyama, H.; Takano, M.; Uchino, K.
1987ICRC....1..277S Altcode: 1987ICRC...20a.277S
No abstract at ADS
---------------------------------------------------------
Title: The solar-terrestrial science programme.
Authors: Wenzel, K. -P.; Domingo, V.; Schmidt, R.
1987ESABu..50....8W Altcode:
The prime objective of the STSP (solar-terrestrial science programme)
Cornerstone is to attack outstanding scientific problems in solar,
heliospheric and space plasma physics in a unified and co-ordinated
manner.
---------------------------------------------------------
Title: Diffuse gamma-rays with energies greater than
1×10<SUP>14</SUP>eV observed in the southern hemisphere.
Authors: Suga, K.; Toyoda, Y.; Kamata, K.; Murakami, K.; Lapointe,
M.; Gaebler, J.; Escobar, I.; Saavedra, O.; Domingo, V.; Shibata,
S.; Akiyama, H.; Takano, M.; Uchino, K.
1987ICRC....1..310S Altcode: 1987ICRC...20a.310S
The data of extensive air showers with low content of muons and
hadrons, observed in the period 1964 to 1966 at Mt. Chacaltaya have
been reanalyzed. The authors try to explain the very high flux.
---------------------------------------------------------
Title: Ground-based measurements of solar intensity oscillations
Authors: Jimenez, A.; Palle, P. L.; Roca Cortes, T.; Domingo, V.;
Korzennik, S.
1987A&A...172..323J Altcode:
Ground-based multichannel photometry of integral sunlight has been
obtained at Izaña (Tenerife) during three months in 1984 with a
photometer built at ESTEC. Power spectra of solar irradiance variations
of individual days show power in the 5 min band just above noise at
a level comparable to the one found from the SMM data (Woodard and
Hudson, 1983). Previous similar ground work had never achieved the
signal level required at the 5 min interval. When combining the best
7 contiguous days of data, the signature of p mode solar oscillations
spectra appears, but individual identification is difficult due to a
low signal-to-noise ratio.
---------------------------------------------------------
Title: Results of the solar constant experiment onboard Spacelab 1.
Authors: Crommelynck, D. A.; Brusa, R. W.; Domingo, V.
1986SoPh..107....1C Altcode: 1987SoPh..107....1C
A cavity type absolute radiometer was flown on Spacelab 1 in
December 1983. We obtain a value of the solar constant of 1361.5 W
m<SUP>−2</SUP> with an estimated accuracy of ±2.3 W m<SUP>−2</SUP>
or 0.17%. When comparing this with other recent determinations,
we find discrepancies which we consider indicative of metrological
problems in present day absolute radiometry.
---------------------------------------------------------
Title: Low-energy particle events and solar filament eruptions
Authors: Sanahuja, B.; Heras, A.; Domingo, V.; Joselyn, J. A.
1986AdSpR...6f.277S Altcode: 1986AdSpR...6..277S
Over the period from August 1978 to October 1982, several large
low-energy (E < 1.6 Mev) proton events associated with interplanetary
travelling disturbances observed at 1 AU by ISEE-3, appeared not to be
triggered by solar flares. Six of them can be associated with filament
eruptions as the source of the disturbances. We have made a comparative
study of the particle fluxes in the interplanetary medium, as well as
of the available H-alpha observations and X-ray and radio emission,
between these events and those associated with disturbances generated
by solar flares.
---------------------------------------------------------
Title: The Ultra Heavy Cosmic Ray Experiment on LDEF-1
Authors: Osullivan, D.; Thompson, A.; Wenzel, K. -P.; Domingo, V.
1985crhe.work..302O Altcode:
The DIAS-ESTEC ultraheavy-cosmic-ray experiment was deployed
in earth orbit aboard the LDEF by the Space Shuttle on April 6,
1984. A large-area (12-sq m) solid-state nuclear-track-detector array,
designed to study the charge spectrum of nuclei with Z = 30 or greater,
is to remain in orbit until recovery of the LDEF by a second Shuttle
mission in March 1985. Details of the background to the experiment,
its astrophysical significance, analysis, and general expectations are
discussed. The impact of recent results on the registration-temperature
effect for ultraheavy nuclei on overall charge resolution is assessed.
---------------------------------------------------------
Title: Solar Irradiance Observations
Authors: Crommelynck, D.; Domingo, V.
1984Sci...225..180C Altcode:
The absolute radiometer on Spacelab 1 was used to obtain solar
irradiance observations from space. A number of effects must be taken
into account in the data reduction. A provisional value was obtained
for the mean solar constant during the observation period (6 to 8
December 1983).
---------------------------------------------------------
Title: A high-resolution study of ultra-heavy cosmic-ray nuclei
(A0178)
Authors: O'Sullivan, D.; Thompson, A.; O'Ceallaigh, C.; Domingo, V.;
Wenzel, K. P.
1984ldef.rept..101O Altcode:
The main objective of the experiment is a detailed study of the charge
spectra of ultraheavy cosmic-ray nuclei from zinc (Z = 30) to uranium
(Z = 92) and beyond using solid-state track detectors. Special emphasis
will be placed on the relative abundances in the region Z or - 65, which
is thought to be dominated by r-process nucleosynthesis. Subsidiary
objectives include the study of the cosmic-ray transiron spectrum a
search for the postulated long-lived superheavy (SH) nuclei (Z or =
110), such as (110) SH294, in the contemporary cosmic radiation. The
motivation behind the search for super-heavy nuclei is based on
predicted half-lives that are short compared to the age of the Earth
but long compared to the age of cosmic rays. The detection of such
nuclei would have far-reaching consequences for nuclear structure
theory. The sample of ultraheavy nuclei obtained in this experiment
will provide unique opportunities for many tests concerning element
nucleosynthesis, cosmic-ray acceleration, and cosmic-ray propagation.
---------------------------------------------------------
Title: Low-Energy Protons Associated with the 14-18 August 1979 Events
(smy/stip Event no.
Authors: Sanahuja, B.; Domingo, V.; Wenzel, K. -P.
1984sii..conf..195S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Low-Energy Protons Associated with the 4 April 1980 Event
(smy/stip Event no. 2.)
Authors: Sanahuja, B.; Domingo, V.; Wenzel, K. -P.
1984sii..conf..229S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Energetics and Interplanetary Effects of the August 14 and 18,
1979 Solar Flares: Summary of Observations Made during the Smy/stip
Event no.
Authors: Kane, S. R.; Bird, M. K.; Domingo, V.; Gapper, G. R.; Green,
G.; Hewish, A.; Howard, R. A.; Iwers, B.; Jackson, B. V.; Koren, U.;
Kunow, H.; McGuire, R. E.; Muller-Mellin, R.; Rompolt, B.; Sanahuja,
B.; Sawant, H. S.; Stewart, R. T.; von Rosenvinge, T.; Wibberenz,
G.; Zlobec, P.
1984sii..conf..175K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The L<SUB>1</SUB>-lagrangian point orbit as a suitable site
for helioseismologic measurements
Authors: Domingo, V.; Wyn-Roberts, D.
1984MmSAI..55..375D Altcode:
The orbit around the Earth - Sun Lagrangian point L<SUB>1</SUB>
has the advantages of providing continuous solar viewing and
eliminating the Earth rotation velocity when compared with ground-based
observations. ESA has completed a study on a spacecraft (DISCO) which
was to have been placed in this orbit, and is now studying a potential
solar observatory (SOHO) to be placed in the same orbit. The aims of
SOHO are the understanding of the solar wind origin and of the heating
and energy balance of the corona and the investigation of the solar
interior structure.
---------------------------------------------------------
Title: An extensive solid state nuclear track detector array for the
study of ultra heavy cosmic ray nuclei aboard the NASA Long Duration
ExposureFacility (LDEF).
Authors: Thompson, A.; O'Sullivan, D.; Wenzel, K. -P.; Domingo, V.;
O'Ceallaigh, C.; Daly, J.; Smit, A.
1984NTRM....8..575T Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Low-Energy Protons Associated with the Events of 10 April,
24 April and 8 may 1981 (stip Interval Xii)
Authors: Sanahuja, B.; Domingo, V.
1984sii..conf..307S Altcode: 1984STIA...8516082S
One of the two flares of 10 April 1981 (1117 UT and 1650 UT) and the
24 April (1400 UT) and 8 May (2232 UT) produced interplanetary shocks
that were accompanied by a large increase of low-energy protons (35-1600
keV). An interesting large shock event is observed on 11 April. Although
the shocks are of very different characteristics, all have the common
feature that the flow of particles up- and downstream is always from
the shock, indicating the shock is the main proton acceleration source
at this energy.
---------------------------------------------------------
Title: Low-energy protons associated with interplanetary shocks as
an independent population in the solar wind
Authors: Sanahuja, B.; Domingo, V.
1984AdSpR...4b.319S Altcode: 1984AdSpR...4..319S
We investigate the large scale flow pattern of 36-1600 keV protons
observed in association with several large interplanetary shocks on
ISEE-3 between August 1978 and April 1980. The distribution function in
the solar wind frame and its temperal evolution indicates that these
particles can behave as a coherent population in the solar wind. This
population propagates along the magnetic field in the same direction as
the solar wind flow, ahead of the shock, and in the opposite direction
after the passage of the perturbed region associated with the shock.
---------------------------------------------------------
Title: The Ultra Heavy Cosmic Ray Experiments on the NASA Long
Duration Exposure Facility (ldef)
Authors: O'Sullivan, D.; Thompson, A.; Daly, J.; O'Ceallaigh, C.;
Wenzel, K. P.; Domingo, V.; Smit, A.
1983ICRC....9..403O Altcode: 1983ICRC...18i.403O
A large array (≅20 m<SUP>2</SUP>sr) of solid state nuclear track
detectors is being prepared for a twelve month exposure in earth orbit
aboard the NASA LDEF. The experiment is designed to study the charge
spectrum of cosmic ray nuclei with Z > 30, particularly of those
above Z ≡ 70.
---------------------------------------------------------
Title: The Ultra Heavy Cosmic Ray Experiment on the NASA Long Duration
Exposure Facility (ldef)
Authors: O'Sullivan, D.; Thompson, A.; Daly, J.; O'Ceallaigh, C.;
Wenzel, K. P.; Domingo, V.; Smit, A.
1983ICRC....8..126O Altcode: 1983ICRC...18h.126O
The experiment is designed primarily to investigate the charge spectrum
of cosmic ray nuclei with Z greater than or equal to 30. This is
to be done by obtaining a larger sample of events than has hitherto
been possible by balloon or satellite exposures. A very large array
of solid state nuclear track detectors is to be exposed in space for
approximately one year. Special emphasis will be placed on the relative
abundances in the region where Z is greater than or equal to 65, which
is thought to be dominated by r-process nucleosynthesis. Among the
subsidiary objectives of the experiment are the study of the cosmic
ray transition spectrum and a search for the postulated long-lived
superheavy nucley (Z greater than or equal to 110) in the contemporary
cosmic radiation. It is noted that the search for super-heavy nuclei
is based on predicted half-lives that are short in comparison with
the age of the earth but long in comparison with the age of cosmic
rays. The far-reaching consequences for nuclear structure theory that
the detection of such nuclei would have are noted.
---------------------------------------------------------
Title: Report on the scientific satellites of the European Space
Agency
Authors: Burke, W. R.; Bennett, K.; Benvenuti, P.; Domingo, V.; Emery,
R. J.; de Graauw, T.; Knott, K.; Macchetto, F.; Marsden, R. G.; Page,
D. E.
1983STIN...8332831B Altcode:
The missions and status of Cos-B Geos 1 and 2, ISEE, and IUE are
outlined. The first Spacelab payload; EXOSAT; and the International
Solar Polar Mission are described. The ESA contribution to the Space
Telescope program; the Hipparcos astrometry program; the Giotto Halley's
Comet mission; and the Infrared Space Observatory project are described.
---------------------------------------------------------
Title: A Large Proton Event Associated with Solar Filament Activity
Authors: Sanahuja, B.; Domingo, V.; Wenzel, K. -P.; Joselyn, J. A.;
Keppler, E.
1983SoPh...84..321S Altcode:
We report observations made from several interplanetary spacecraft,
of the large low-energy particle event of 23-27 April, 1979 associated
with solar filament activity. We discuss the intensity, spectral and
directional evolution of the event as observed in the energy range
35-1600 keV on ISEE-3, located ∼ 0.99 AU from the Sun upstream of
the Earth. We demonstrate that the shock disturbance propagating
through the interplanetary medium and observed at ISEE-3 on 24/25
April strongly controls the particle event. From a comparison of the
ISEE-3 observations with those on other spacecraft, in particular on
Helios-2, located at 0.41 AU heliocentric distance near the Sun-Earth
line, we identify the solar filament erupting on late 22 April near
central meridian as the trigger for the propagating shock disturbance.
---------------------------------------------------------
Title: La magnetosfera terrestre. Un acelerador de partículas
cargadas.
Authors: Domingo, V.
1983POEM...14...83D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Energetics and interplanetary effects of the August 14 and 18,
1979 solar flares
Authors: Kane, S. R.; Bird, M. K.; Domingo, V.; Green, G.; Gapper,
G. R.; Hewish, A.; Howard, R. A.; Iwers, B.; Jackson, B. V.; Koren, U.
1983STIN...8329164K Altcode:
The STIP Event No. 1, which covered the time interval August 14 - 18,
1979, was characterized by two energetic flares: one on August 14
(approximately 1243 UT) and the other on August 18 (approximately
1400 UT). The hard X-ray, soft X-ray, optical, radio and energetic
particle emissions from these flares and their interplanetary effects
were observed with many instruments in space and on the ground. A
summary of some of these observations is presented. The results of
a preliminary analysis relevant to the acceleration of particles,
coronal transients and evolution of shocks are as follows: (1) During
the August 14 flare energetic particles were probably accelerated
but could not escape the Sun in large numbers. On the other hand,
during the August 18 flare the acceleration of high energy particles
occurred relatively high in the corona, from whence they could easily
escape into interplanetary space but could not penetrate down to the
lower altitudes in the solar atmosphere in large numbers. (2) The
kinetic energy of the coronal transient associated with the August 14
flare was much larger than the total energy of energetic electrons,
indicating an additional energy source for the transient. (3) The shock
associated with the August 18 flare extended to greater than 2 (3.14)
steradians. The shock maintained its speed from the flare site to a
distance of approximately 35 R and then decelerated to a distance of
approximately 1 AU as approximately R to the minus 0.8 power.
---------------------------------------------------------
Title: Disco - a solar-seismology and heliospheric-structure
observatory.
Authors: Domingo, V.
1982ESABu..32...16D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Consequences of solar-related processes on the earth's
environment and man's devices.
Authors: Gendrin, R.; Domingo, V.
1982sspf.conf...71G Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Consequences of solar-related processes on the Earth's
environment and man's devices
Authors: Gendrin, R.; Domingo, V.
1982AdSpR...2a..71G Altcode: 1982AdSpR...2...71G
The effects of solar disturbances on the earth environment and on
anthropogenic systems and devices are discussed. Attention is given
to solar cosmic ray effects on the atmosphere, which may produce
an increase in D region electron density giving rise to polar cap
absorption events, modulations of galactic cosmic ray flux affecting
atmospheric electric fields, and solar wind-ionosphere coupling which
may exert an influence on terrestrial meteorology. Solar wind effects
on the magnetosphere-ionosphere-atmosphere system as evidenced by the
auroral electrojet, magnetospheric substorms and auroral heating are
then considered in relation to their consequences for large, conducting
man-made systems and geomagnetic surveys at high latitudes, spacecraft
charging and performance and satellite lifetimes. The effects of human
activities, both scientific and industrial, on the magnetosphere are
also pointed out.
---------------------------------------------------------
Title: The Solar Grazing Incidence / GRIST / and Optical / SOT =
Solar Optical Telescope / Joint Accommodations
Authors: Domingo, V.
1981SSRv...29..327D Altcode:
Some of the problems foreseen for the joint accommodation and operation
of the Grazing Incidence Solar Telescope (GRIST) under study by ESA to
operate in the extreme ultraviolet region (90 < λ < 1700 Å),
and the Solar Optical Telescope (SOT), developed by NASA to operate
in the ultraviolet, optical and infrared region (A > 1100 Å)
on a Spacelab mission are described.
---------------------------------------------------------
Title: Physics of solar variations
Authors: Domingo, V.
1981SoPh...74.....D Altcode:
Topics discussed include the sun (structure, oscillations, magnetic
cycle, surface variations), solar radiation, solar radiation effects in
the earth's atmosphere, long-term variations (climate and paleoclimate),
and instrumentation. Papers are presented on short-period intensity
fluctuations of integral sunlight, on the theory of the solar cycle,
and on the nonsymmetric solar dynamo. Attention is also given to
solar radiation and its variation in time, to the effects of solar
variations on the upper atmosphere, and to the role of space techniques
in understanding solar variability.
---------------------------------------------------------
Title: Introduction - Physics of Solar Variations
Authors: Domingo, V.
1981SoPh...74....7D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On the location of the source for the energetic electron layer
at the polar magnetopause and its relation to magnetic reconnection
Authors: Formisano, V.; Domingo, V.; Wenzel, K. -P.
1981JGR....86.4579F Altcode:
The existence of a layer of energetic (>20 keV) electrons
along the magnetopause, extending from the polar cusp region to the
distant magnetotail, has been established by measurements on various
spacecraft. We have performed a statistical study of electron flux
and spectral measurements above 0.5 MeV observed in different regions
of the magnetopause accessible to HEOS 2, with the aim of identifying
the source for this magnetopause electron layer. The measurements along
the polar magnetotail (i. e., adjacent to the plasma mantle), along the
mid-latitude dayside magnetopause (i.e.,adjacent to the dayside plasma
boundary layer), and on both sides of the magnetosheath/polar cusp
interface (i.e., in the exterior polar cusp and in the entry layer) have
been separately analyzed and are statistically compared. We conclude
that escape of electrons from the magnetosphere can be excluded as a
significant source for the tail magnetopause layer on the basis of the
observed intensities, of the spectra, and of the frequency of appearance
of electrons outside those magnetopause regions which lie adjacent to
the outer trapping zone. The electron intensities in the exterior polar
cusp region are found to be correlated with the north/south component
of the interplanetary magnetic field (IMF). High intensity levels
are observed when the IMF is directed southward (B<SUB>z</SUB><0),
and low levels when the IMF points northward (B<SUB>z</SUB>>0). The
electron flux in the exterior cusp region at times of southward IMF
and at the near-earth polar magnetotail at times of northward IMF
is well correlated with the number of field lines carried by the
solar wind towards the magnetosphere (expressed by the product of
solar wind speed and interplanetary field magnitude). We interpret
this as strong evidence that acceleration processes associated with
magnetic reconnection occur at the magnetopause at those times. Local
acceleration near the high-latitude magnetopause appears therefore to
be a prime source for the magnetopause electron layer.
---------------------------------------------------------
Title: Non-Flare Injection of Protons Into Interplanetary Space
Authors: Domingo, V.; Sanahuja, B.; Wenzel, K. -P.
1981ICRC....3..109D Altcode: 1981ICRC...17c.109D
The superimposition of a second proton population associated with a
solar wind regime, and bounded by a pair of shocks, is found to be
superimposed upon the first in an investigation of 35-1600 KeV solar
protons observed during an April, 1979 nonflare event by ISEE-3. The
source of the particles and the solar wind regime appear to be closely
associated with intense solar filament activity near the central
meridian. The temporal evolution of velocity spectra and anisotropy
distributions during this period are discussed.
---------------------------------------------------------
Title: Anisotropy Characteristics of Upstream Proton Events
Authors: Sanderson, T. R.; Domingo, V.; Reinhard, R.; Wenzel, K. -P.
1981ICRC....3..483S Altcode: 1981ICRC...17c.483S
Results are presented of a detailed analysis of proton anisotropies
observed during an upstream event when ISEE-3 was approximately
80 earth radii upstream from the earth, and close to the sun-earth
radial. During the first part of the event, particles were observed
streaming mainly from the direction of the earth along the magnetic
field. Later in the event, the angular distributions broadened until
towards the end of the event, approximately equal intensities were
observed with pitch angles from 0 deg up to 120 deg, with essentially
no particles with pitch angles close to 180 deg. (Here a 0 deg pitch
angle particle is defined as a particle moving upstream along the
magnetic field.) Large amplitude low-frequency waves were observed
in the magnetic field at ISEE-3 whenever enhanced fluxes of 90 deg
protons were observed. It is argued that the 90 deg protons are the
result of pitch angle scattering of the upstream moving protons in
the region between the bow shock and ISEE-3.
---------------------------------------------------------
Title: Propagation of upstream protons in the near-earth solar wind
Authors: Domingo, V.; Sanderson, T. R.; Wenzel, K. -P.
1981AdSpR...1c.125D Altcode: 1981AdSpR...1..125D
The propagation of energetic protons (35-1600 keV) from the Earth's
magnetosphere to the ISEE-3 spacecraft located about 240 earth radii
(R<SUB>E</SUB>) upstream in the solar wind is used as a tool to study
the interaction between these protons and the solar wind. In this
preliminary study we present proton pitch angle distributions seen at
different times during the development of upstream events that occur
in relatively quiet interplanetary conditions. In general a highly
anisotropic sunward flow is seen at the beginning of the events. During
the course of the events pitch angle distributions may vary between
streaming along the field lines (peaked around 0° pitch angle),
a uniform intensity between 0° and 90°, and a peaked distribution
around a preferred pitch angle that is often near 90°.
---------------------------------------------------------
Title: Propagation of upstream protons in near-earth solar wind.
Authors: Domingo, V.; Sanderson, T. R.; Wenzel, K. -P.
1981crh..conf..125D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Control of Energetic Particle Flows by the Interplanetary
Magnetic Field Structure
Authors: Reinhard, R.; Formisano, V.; Wenzel, K. P.; Domingo, V.
1981sowi.conf..490R Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Intensity Decay Patterns for Proton Particle Increases
Associated with Interplanetary Shock Waves
Authors: Hynds, R. J.; Domingo, V.
1981ICRC....3..447H Altcode: 1981ICRC...17c.447H
At 1 AU the passage of interplanetary shock waves is associated with
long-time, constant increases in intensity of low energy protons,
called Energetic Storm Particle (ESP) events. The characteristc
pattern involves an initial rise in particle intensity up to 12
hours prior to the passage of the shock; the intensity peaks at or
near the shock front, followed by a relative smooth decay after the
passage of the shock. For protons of energies less than or equal to
30 keV, the intensity decay after the passage of the shock can show
considerable variation. The particle data are compared to interplanetary
magnetic field and solar wind data, showing that these abrupt changes
in intensity are associated with interplanetary plasma and field
conditions. Data from the Energetic Proton Anisotropy Spectrometer
on the ISEE-3 spacecraft is used to investigate a typical ESP event
(February 17-23, 1979).
---------------------------------------------------------
Title: Prediction of energetic particle disturbances
Authors: Paulikas, G. A.; Baker, D. N.; Barron, W. R.; Domingo, V.;
Higbie, P. R.; Imhof, W. L.; Lyons, L. R.; McPherron, R. L.; Roelof,
E. C.; Scholer, M.
1979stp.....2..415P Altcode:
The prediction of fluxes of energetic particles of solar or
magnetospheric origin is addressed. Topics include the prediction of
the properties of the particle populations generated by magnetospheric
storms and substorms, and the prediction of long term variations in
the populations of magnetospheric particles.
---------------------------------------------------------
Title: Energetic Electrons in the Cusp and in the High Latitude
Plasma Sheet - Evidence for Source Regions
Authors: Formisano, V.; Domingo, V.
1979P&SS...27.1479F Altcode:
HEOS-2 has observed energetic electrons (> 40 keV) in the high
latitude magnetosphere appearing as one or more peaks outside
and often well separated from the trapping boundary. Most of the
observations are between 70° and 80° invariant latitudes both in
the day and nightside. The peaks are located in the dayside adjacent
to the polar cusp and coincide in the nightside with the edge of the
plasma sheet. The electron peak intensity on the nightside shows a
clear correlation with AE. The electron peak intensities on the dayside
exceed those on the nightside and are generally higher in the pre-noon
than in the afternoon sector. Observations on the dayside in the distant
cusp region and in the adjacent magnetosheath show high and fluctuating
intensities of energetic electronswith an energy spectrum much harder
than in the outermost trapping region. This observational evidence
suggests different source regions for these energetic electrons: one
in the distant geomagnetic tail and another one around the dayside
cusp indentation.
---------------------------------------------------------
Title: The three-dimensional shape of the magnetopause
Authors: Formisano, V.; Domingo, V.; Wenzel, K. -P.
1979P&SS...27.1137F Altcode:
Nearly 1000 magnetopause crossings from HEOS-2, HEOS-1, OGO-5 and 5
IMP space-craft covering most of the northern and part of the southern
dayside and near-Earth tail magnetopause ( X >-15 R<SUB>E</SUB>) have
been used to perform a detailed study of the three-dimensional shape
and location of the magnetopause. The long-term influence of the solar
wind conditions on the average magnetopause geometry has been reduced by
normalising the radial distances of the observed magnetopause crossings
to an average dynamical solar wind pressure. Best-fit ellipsoids
have been obtained to represent the average magnetopause surface in
geocentric solar ecliptic (GSE) and (as a function of tilt angle) in
solar magnetic (SM) coordinates. Average geocentric distances to the
magnetopause for the 1972-1973 solar wind conditions (density 9.4 cm
<SUP>-3</SUP>, velocity 450 km s <SUP>-1</SUP>) are 8.8 R<SUB>E</SUB>
in the sunward direction, 14.7 R<SUB>E</SUB> in the dusk direction,
13.4 R<SUB>E</SUB> in the dawn direction and 13.7 R<SUB>E</SUB> in
the direction normal to the ecliptic plane. The magnetopause surface
is tilted by 6.6° ± 2° in a direction consistent with that expected
from the aberration effect of the radial solar wind. Our data suggest
that the solar wind plasma density and the interplanetary magnetic
field (IMF) orientation affect the distance to the polar magnetopause,
larger distances corresponding to higher plasma density and southward
fields. Our best-fit magnetopause surface shows larger geocentric
distances than predicted by the model of Choe et al. [ Planet Space
Sci. 21, 485 (1973).] normalised to the same solar wind pressure.
---------------------------------------------------------
Title: Total Solar Energy Output and its Measurement
Authors: Domingo, V.
1979BAAS...11..423D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Total solar energy output and its measurement.
Authors: Domingo, V.
1979BAAS...11..422D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Magnetospheric Bursts at Proton Energies above 35 KEV. Observed
from the ISEE-3 Spacecraft
Authors: Hynds, R. J.; Balogh, A.; Domingo, V.; Wenzel, K. -P.
1979ICRC....3..154H Altcode: 1979ICRC...16c.154H
No abstract at ADS
---------------------------------------------------------
Title: a High Resolution Study of Ultra Heavy Cosmic Ray Nuclei
Using the Long Duration Exposure Facility (ldef)
Authors: Thompson, A.; O'Sullivan, D.; Daly, J.; O'Ceallaigh, C.;
Domingo, V.; Smit, A.; Wenzel, K. -P.
1979ICRC...11..103T Altcode: 1980ICRC...11..103T; 1979ICRC...16k.103T
A large array of nuclear track detectors is being prepared for a
twelve month exposure in space aboard the LDEF which is scheduled to be
launched by the NASA Space Shuttle in 1981. The experiment is designed
to study the charge spectrum of cosmic ray nuclei with Z greater than
30 by obtaining a large and more uniform sample of events than has
hitherto been possible by balloon or satellite exposures. A summary
of the astrophysical significance of the experiment and its current
state of development is given.
---------------------------------------------------------
Title: a Solar Proton Event of Possible Non-Flare Origin
Authors: Domingo, V.; Hynds, R. J.; Stevens, G.
1979ICRC....5..192D Altcode: 1979ICRC...16e.192D; 1980ICRC....5..192D
The sun showed little activity in the period August 18-23, 1978. A
filament, near central meridian passage, disappeared at approximately
0120 U.T. on August 23, with a SSC recorded at earth at 0247 U.T. on
August 27 that appears to be associated with it. On August 25, the
low-energy proton detector on board the ISEE-3 spacecraft detected a
particle increase which commenced prior to mid-day, and lasted until
about 1730 U.T. on August 27. Data for the event are displayed and
the possible origin of the particles is discussed.
---------------------------------------------------------
Title: Rigidity-independent coronal propagation and escape of solar
protons and α particles
Authors: Perron, C.; Domingo, V.; Reinhard, R.; Wenzel, K. -P.
1978JGR....83.2017P Altcode:
A statistical study of 42 solar proton and α particle events has been
performed in the energy range of 9-36MeV/nucleon (nuc) as measured by
the Space Science Department/European Space Agency experiment on Heos 2
during 1972-1974. From one event to another there is a high variability
of the p/α ratio at equal energy per nucleon ranging from about 4
to 1000 at 10 MeV/nuc. It is found that the lower value of the p/α
ratios increases with azimuthal distance from the flare site. We show
that this is not the result of rigidity-dependent coronal processes but
that the increase follows rather as a consequence of two observations:
(1) the p/α ratio is correlated with the size of the particle
event (Van Hollebeke, 1975) and (2) the number of observed particle
events decreases to the east as is found by numerous authors. A model
calculation based on these observations is in good agreement with the
data. The conclusion of rigidity-independent coronal propagation and
escape also follows from other observations. First, the p/α ratios
simultaneously measured by the University of Chicago experiment on
board Pioneer 10 and 11, which have different connection longitudes, are
generally the same as the Heos 2 values. Second, no systematic variation
of the p/α ratio is found for the few cases of large individual events,
when the p/α ratio can be followed over an extended time period, i.e.,
over an extended range of connection longitudes. Third, the proton
and α particle spectral exponents show no systematic variation with
heliolongitude. It is concluded that the observed large variations of
the p/α ratio from event to event are essentially due to different
acceleration or storage conditons at the flare site.
---------------------------------------------------------
Title: Where do charged particles enter in and exit from the
magnetosphere? Some HEOS-2 measurements.
Authors: Domingo, V.; Page, D. E.; Wenzel, K. -P.
1978JATP...40..279D Altcode:
The orbit of HEOS-2 through the northern polar magnetosphere was such
that it was possible to monitor the motion of solar protons at the
polar magnetopause and across the geomagnetic tail. The large-particle
intensity was found to increase as the magnetopause was approached. The
inner magnetosphere appears to be partially shielded by the magnetopause
from solar particles. The characteristics of an essentially permanent
layer of energetic and relativistic electrons were also monitored
by HEOS-2. This layer was detected in about 90% of the orbits over a
period of 25 months. It was located at or around the magnetopause. The
electron intensity in the magnetopause spike seems to fall off with
distance along the tail away from the earth. This is consistent with
the idea that the electrons originate near the earth.
---------------------------------------------------------
Title: On the mechanism of plasma penetration and energetic electron
escape across the dayside magnetopause.
Authors: Formisano, V.; Domingo, V.; Wenzel, K. -P.
1978JATP...40..293F Altcode:
A statistical study of correlated observations of plasma, energetic
(above 40 keV) electrons and magnetic fields on HEOS-2 in the outer
dayside magnetosphere and magnetosheath has been performed. It is found
that on the dayside magnetosphere the occurrence of plasma inside
the magnetopause is anticorrelated with the appearance of energetic
electrons in the magnetosheath. A mechanism is derived that attempts
to explain how plasma may penetrate across the magnetopause into the
magnetosphere and how energetic electrons may escape from the (pseudo)
trapping region in the dayside magnetosphere into the magnetosheath. The
mechanism is an E X B drift across the magnetopause. The drift is
directed inward or outward depending on the direction of the electric
field at the magnetopause.
---------------------------------------------------------
Title: Interplanetary magnetic field and geomagnetic activity.
Authors: Domingo, V.
1978spre.conf..325D Altcode: 1978spre.proc..325D
The interaction between the interplanetary magnetic field (IMF) and the
geomagnetic field is investigated using a compilation of 34,670 hr of
data on IMF and solar-wind parameters, as well as the Kp index as an
indicator of geomagnetic activity. Correlations between geomagnetic
activity and solar-wind parameters are analyzed, and it is found that
geomagnetic activity is apparently only indirectly related to the
interaction between the IMF and the geomagnetic field. The results
indicate that the interaction between the geomagnetic field and the
IMF dominates the solar-wind interaction with the magnetosphere, is
governed by folding of the IMF lines of force around the magnetosphere,
and extends throughout the magnetopause.
---------------------------------------------------------
Title: Energetic electrons in the outer magnetosphere at mid to
high latitudes
Authors: Domingo, V.; Wenzel, K. -P.
1978spre.conf..313D Altcode: 1978spre.proc..313D
Results are reported for coordinated HEOS 2 electron and magnetic-field
observations in the zone of unstable (variable) radiation at middle
to high latitudes in the northern magnetosphere. The observations
are discussed in terms of dayside closed field lines, the flanks of
the magnetotail, and the distribution of variable electron fluxes
observed in the outer magnetosphere. It is found that: (1) the
electron population of the dayside pseudotrapping region extends out
to the magnetopause at medium and high latitudes; (2) in the flanks
of the magnetotail the electron population extends to high latitudes
along the horns discovered at low latitudes by Frank et al. (1963);
(3) the horn on the morning side appears to be populated by higher
electron intensities and to extend to higher latitudes than that on
the evening side; and (4) the electron fluxes in the flanks of the
magnetotail appear to be a continuation of those encountered in the
dayside pseudotrapping region and exhibit properties similar to those
observed for electrons encountered in the magnetopause electron layer
and in the magnetosheath.
---------------------------------------------------------
Title: Influence of the magnetosheath on solar proton penetration
into the magnetosphere
Authors: Domingo, V.; Wenzel, K. -P.
1977P&SS...25.1111D Altcode:
The observation of solar protons (1-9 MeV) aboard HEOS-2 in the
high-latitude magnetotail and magnetosheath on 9 June 1972, and their
comparison with simultaneous measurements on Explorers 41 and 43,
both in interplanetary space, indicate the existence of a distinct
region of the inner magnetosheath (about 3 Earth radii thick) near the
high-latitude magnetopause in which the solar particle flow is almost
reversed with respect to the flow observed in interplanetary space. The
region can also be seen by comparing magnetic field measurements on the
three spacecraft. The observations in the outer layer of the magnetotail
show solar protons predominantly entering the magnetosphere somewhere
near the Earth, perhaps the cusp region.
---------------------------------------------------------
Title: Energetic and relativistic electrons near the polar
magnetopause
Authors: Domingo, V.; Page, D. E.; Wenzel, K. -P.
1977JGR....82.2327D Altcode:
More than 2 years of Heos 2 observations in the high-latitude outer
magnetosphere and magnetosheath have confirmed the presence of a
layer of energetic and relativistic electrons near the polar tail
magnetopause. This layer, appearing as ‘electron spike’ on almost
every magnetopause crossing, contains electrons over a wide range of
energies up to relativistic energies of >2 MeV. Their differential
energy spectrum, if fitted by a power law, has an average spectral
index between 3 and 4.5. The spikes are typically 1-2 R<SUB>E</SUB> wide
extending more into the magnetosheath than into the magnetosphere. The
electron intensity in the magnetopause layer decreases with distance
along the tail, away from the polar cusp, and increases with increasing
Kp values. It tends to be higher when the magnetosheath field is
parallel or antiparallel to the tail magnetic field. In many cases
the magnetopause spikes are accompanied by spikes in the magnetosheath
which often follow closely the fluctuations of the magnetosheath field
direction and/or intensity. A map of the average electron distribution
in the polar magnetosphere and magnetosheath is presented.
---------------------------------------------------------
Title: Interplanetary magnetic field and geomagnetic activity
Authors: Domingo, V.
1977IA&A...29...11D Altcode:
A vectorial treatment of the geomagnetic field and interplanetary
magnetic field (IMF) is attempted with the object of shedding light
on interaction between the fields. Advantages and drawbacks of the
three-hour planetary index Kp are considered; the Kp is relied upon
in the analysis. Data referable to nearly 35,000 hours during which
the velocity of the fields were observable are considered. The kinetic
effects of the solar wind perceived in terms of solar wind velocity are
found independent of electromagnetic effects. The interaction between
the IMF and the geomagnetic field is found maximized when the fields
are antiparallel in the equatorial zone and minimized when the angle
formed between them is in the 30-50 deg range, and is an increasing
function of the intensity of the IMF.
---------------------------------------------------------
Title: The March 5, 1972 Solar Event: Coronal Control of Particle
Release
Authors: Reinhard, R.; Domingo, V.; Perron, C.; Wenzel, K. -P.
1977ICRC....5..107R Altcode: 1978ICRC....5..107R; 1977ICRC...15e.107R
The time-intensity profiles of 1-9-MeV and 9-36-MeV protons observed
by the ESA/SSD detector system on HEOS 2 during the March 5, 1972,
event display a number of unusual features. The most prominent is a
plateaulike peak lasting for almost a day. When mapping the particle
fluxes back to the sun, it is seen that the plateau is caused by a
large chromospheric polarity cell which is 60 to 100 deg away from
the acceleration region and uniformly populated with particles. A
short-lived (3 h) particle intensity increase with strong sunward flow
is observed during the decay phase and tentatively associated with a
magnetic loop-type structure in the interplanetary medium.
---------------------------------------------------------
Title: Rigidity Independent Coronal Propagation and Escape of Solar
Protons and Alpha Particles
Authors: Perron, C.; Domingo, V.; Reinhard, R.; Wenzel, K. -P.
1977ICRC....5..113P Altcode: 1977ICRC...15e.113P
No abstract at ADS
---------------------------------------------------------
Title: Generation and propagation of charged particles in the solar
event of 22 July 1972.
Authors: Morosova, E. I.; Pisarenko, N. F.; Volodichev, N. N.; Kolesov,
G. Ia.; Kurt, V. G.; Domingo, V.; Page, D. E.; Wenzel, K. -P.; Smerd,
S. F.
1976spre.conf..775M Altcode: 1976spre.proc..775M
The increase of charged particles, protons with energies up to 500 MeV
and electrons up to about 3.5 MeV, in the solar event on 22 July 1972
is examined. The analysis of the data on the anisotropy of the charged
particles, radio and X-ray observations, and the absence of an optical
flare lead to the conclusion that the increase is associated with
a sympathetic flare in the active region McMath 11958. The powerful
shock wave from the flare, which occurred behind the limb apparently
in the active region McMath 11976, moving along the sun's surface was
the agent which caused this flare. The capture of some of the flare
particles by a trap near the sun led to the possibility of their
prolonged escape into the interplanetary space.
---------------------------------------------------------
Title: Experimental evidence for solar protons following paths
determined by solar wind flow regimes.
Authors: Wenzel, K. -P.; Domingo, V.; Page, D. E.
1976spre.conf..719W Altcode: 1976spre.proc..719W
Experimental results are presented from the solar particle, plasma and
magnetometer experiments on HEOS 2 indicating that solar protons are
constrained to discrete solar wind flow regimes and only with difficulty
move across magnetic field lines to neighboring regimes. An outstanding
example was the period of 29 October-2 November 1972, during which time
HEOS 2 appeared to remain close to a solar wind boundary lying roughly
parallel to the ecliptic plane. Another example of proton collimation
in solar wind regimes was observed during 3-5 November 1973.
---------------------------------------------------------
Title: October 1972 solar event: The third dimension in solar
particle propagation
Authors: Domingo, V.; Page, D. E.; Wenzel, K. -P.
1976JGR....81...43D Altcode:
From late on October 29 until November 3, 1972, our experiment on
the European Space Research Organization satellite Heos 2 recorded
the arrival of an enhanced interplanetary particle intensity. A
dramatic ‘slot’ in count rate and other sudden anisotropy and
flux changes (measured in and perpendicular to the ecliptic plane)
were found to coincide with changes in the θ (north-south) ecliptic
direction of the interplanetary magnetic field. However, reorientation
of strongly field-aligned particle distributions relative to the
detectors was insufficient to explain the intensity changes recorded,
and the conclusion had to be drawn that the spacecraft was repeatedly
crossing a boundary between one regime and a neighboring one with a
different particle population. Since the switching from one regime
to the other continued for several days, it would seem reasonable to
suggest that the boundary between regimes was roughly parallel to the
ecliptic plane. This idea was reinforced by the discovery that each
time that the particle regime changed, not only did B<SUB>θ</SUB>
change, but the solar wind flow direction changed, the dip angle
reversing sign. It would thus appear that when the solar wind blows
three-dimensional snakelike tubes in interplanetary space, MeV
particles obediently follow the field line bundles within such tubes
and experience considerable difficulty in crossing from one tube to
a neighboring tube which encloses a different regime. Because of the
absence of cross-field particle movement, measurements made at higher
solar latitudes, where most solar active regions occur, could reveal a
somewhat different picture of the development of solar particle events.
---------------------------------------------------------
Title: Solar Radiation Variation and Climate
Authors: Domingo, V.
1976ASSL...61...21D Altcode: 1976aps..conf...21D
No abstract at ADS
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Title: Multisatellite observations of solar protons penetrating
the magnetopause.
Authors: Domingo, V.; Page, D. E.; Wenzel, K. -P.
1976ASSL...57..225D Altcode:
Simultaneous observations of low-energy solar protons (1-40 MeV)
by HEOS-2 in the northern high-latitude magnetotail and by other
spacecraft in interplanetary space during the solar proton event of
June 8, 1972 are presented. The results indicate that solar protons
enter that magnetotail lobe which is not well connected to the
interplanetary magnetic field - with respect to solar-particle entry -
preferentially close to the earth rather than farther downtail. The
particle density gradients measured in the tail lobe suggest that
the particles enter there not only across the polar magnetopause,
but also from the neutral sheet.
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Title: On the Propagation of Low Energy Solar Protons in the
Interplanetary Medium
Authors: Amata, E.; Domingo, V.; Page, D. E.; Wenzel, K. P.
1975ICRC....5.1761A Altcode: 1975ICRC...14.1761A
The fluxes and anisotropies of low energy solar protons (less
than 10 MeV) observed on two occasions when the HEOS-2 spacecraft
encountered solar proton streams are studied taking into account the
interplanetary magnetic field and plasma conditions existing at those
times. (Plasma and magnetic field measurements are available from
the same satellite). The variations in the streaming pattern are used
to infer the topological structure of the interplanetary medium. The
observed results are compared to existing models of particle propagation
between the sun and the earth.
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Title: Das solare Ereignis vom 29. Oktober 1972: MeV Protonen,
Alphateilchen und Elektronen
Authors: Wenzel, K. -P.; Domingo, V.; Page, D. E.
1974MitAG..35..266W Altcode:
No abstract at ADS
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Title: MeV Electrons, Protons and Alpha Particles Observed August
2-12 1972
Authors: Page, D. E.; Domingo, V.; Wenzel, K. -P.
1974ASSL...42..573P Altcode: 1974cimo.symp..573P
An experiment was conducted on the ESRO satellite HEOS2 to monitor
electrons, protons, and alpha-particles during specific solar particle
events. Time constants of the decay and the anisotropies observed
for different particle species were studied. Information was obtained
concerning the interplanetary conditions. The conclusions derived from
early particle data were in good agreement with more recent directly
measured interplanetary data.
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Title: Energetic Electrons at the Magnetopause
Authors: Domingo, V.; Page, D. E.; Wenzel, K. -P.
1974ASSL...42..159D Altcode: 1974cimo.symp..159D
Results of observations of energetic and relativistic electrons made by
the highly ecentric ESRO satellite HEOS 2 near the high-latitude tail
magnetopause. There is generally a particle layer near the magnetopause,
containing electrons up to about 1 MeV. The particle intensity shows
a clear dependence on geomagnetic activity.
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Title: Measurements of Solar Protons in the Near Earth Magnetotail
Authors: Domingo, V.; Page, D. E.; Wenzel, K. -P.
1974ASSL...42..507D Altcode: 1974cimo.symp..507D
Preliminary results of the measurement of protons in the high latitude
magnetosphere using the HEOS2 spin stabilized spacecraft. Data were
obtained from the front solid state detector in anticoincidence with
the back detector and the scintillator. The detector was operated
on an angular mode while the channel measured protons of 1 to 9 MeV
and electrons of about 0.4 to 0.6 MeV. Results indicated that the
anisotropy measurement in the near earth magnetotail for protons of
about 1 MeV showed a reasonable gradient of fluxes present in it. It
is possible to use this measurement to map the penetration of protons
into the polar cap.
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Title: Solar particle penetration through the magnetosheath
Authors: Domingo, V.; Page, D. E.; Wenzel, K. -P.
1974stp.....2...96D Altcode:
Data from HEOS-2 and from the NOAA experiment on Explorer 41 are
presented which demonstrate that often the bow shock and magnetosheath
seriously distort the flux of 1-MeV solar particles, so that it is no
longer valid to assume that the magnetopause is the boundary between the
interplanetary medium and the magnetotail. The change in absolute value
and direction of the flux of particles that might be expected to occur
at the magnetopause is not always seen exactly at that point. Rather,
this change occurs sometimes further away in the magnetosheath, and
sometimes the magnetopause looks completely transparent to arriving
energetic particles as if the magnetotail were a continuation of the
magnetosheath.
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Title: Magnetosheath observations at high northern latitudes by Heos 2
Authors: Hedgecock, P. C.; Cerulli, P.; Coletti, A.; Egidi, A.;
Marconero, R.; Domingo, V.; Köhn, D.; Page, D. E.; Taylor, B. G.;
Wenzel, K. -P.
1973JGR....78.1715H Altcode:
No abstract at ADS
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Title: The April 17/18, 1972 Solar Event: Spectral and Directional
Measurements of Protons, Alpha-Particles, and Electrons. (Abstract)
Authors: Wenzel, K. -P.; Domingo, V.; Page, D. E.; Taylor, B. G.
1973ICRC....2.1438W Altcode: 1973ICRC...13.1438W
No abstract at ADS
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Title: The April 17/18, 1972 Solar Event: Spectral and Directional
Measurements of Protons, Alpha-Particles, and Electrons
Authors: Wenzel, K. P.; Domingo, V.; Page, D. E.; Taylor, B. G.
1973ICRC....5.3151W Altcode: 1973ICRC...13.3151W
No abstract at ADS
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Title: High energy electrons at the magnetopause above the north
pole. Preliminary results from the HEOS 2 satellite.
Authors: Page, D. E.; Domingo, V.; Köhn, D.; Taylor, B. G.; Wenzel,
K. -P.; Hedgecock, P. C.
1973spre.conf..631P Altcode: 1973spre....2..631P
No abstract at ADS
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Title: Northern Polar Cap Particle Flux Variations Following the 2
November 1969 Event
Authors: Domingo, V.; Page, E. E.; Shaw, M. L.
1972spen.conf..105D Altcode:
No abstract at ADS
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Title: New Results in Particle Arrival at the Polar Caps
Authors: Page, D. E.; Domingo, V.
1972ASSL...32..107P Altcode: 1972emp..conf..107P
No abstract at ADS
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Title: Two-satellite observation of spatial and temporal particle
flux variations over the polar caps
Authors: Domingo, V.; Page, D. E.
1972JGR....77.1971D Altcode:
No abstract at ADS
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Title: North-South Asymmetry in Polar Cap Regions. (Abstract)
Authors: Domingo, V.; Page, D. E.
1971ICRC....2..825D Altcode: 1971ICRC...12..825D
No abstract at ADS
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Title: North-South Asymmetry in Polar Cap Regions
Authors: Domingo, V.; Page, D. E.
1971ICRC....5.2009D Altcode: 1971ICRC...12.2009D
No abstract at ADS
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Title: North-south asymmetry of solar-particle fluxes in polar-cap
regions
Authors: Domingo, V.; Page, D. E.
1971JGR....76.8159D Altcode:
On January 24, 1969, an experiment on the Esro 1/Aurorae satellite
recorded a flux over the central north pole that at times was a factor
of 7 greater than that seen over the south pole. This asymmetry is
discussed in relation to the interplanetary-field direction measured
at the same time by the Heos spacecraft, and comparison is made with
the opposite asymmetrical configuration observed by Evans and Stone
(1969) on November 2, 1967. From the evidence of two events it would
appear that a southward interplanetary field plays a significant role
in permitting direct access, while the magnitude and polarity of the
asymmetry are determined by, respectively, interplanetary-particle
anisotropy and the ‘toward’ or ‘away’ nature of the field.
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Title: Muons in air showers of energies above 10<SUP>17</SUP> eV
Authors: Suga, K.; Shibata, S.; Mikamo, S.; Toyoda, Y.; Murakami,
K.; Lapointe, M.; Kamata, K.; Domingo, V.
1970ICRC....3..423S Altcode: 1969ICRC....3..423S; 1970ICRC...11c.423S
No abstract at ADS
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Title: Predominantly electromagnetic air showers of energy
10<SUP>14</SUP> eV to 10<SUP>16</SUP> eV
Authors: Kamata, K.; Shibata, S.; Saavedra, O.; Domingo, V.; Suga,
K.; Murakami, K.; Toyoda, Y.; Lapointe, M.; Gaebler, J.; Escobar, I.
1968CaJPS..46...72K Altcode: 1968CaJPh..46S..72K; 1968ICRC...10...72K
No abstract at ADS
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Title: Note on the primary energy spectrum
Authors: Lapointe, M.; Kamata, K.; Gaebler, J.; Escobar, I.; Domingo,
V.; Suga, K.; Murakami, K.; Toyoda, Y.; Shibata, S.
1968CaJPS..46...68L Altcode: 1968ICRC...10...68L; 1968CaJPh..46S..68L
No abstract at ADS
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Title: Studies of primary cosmic rays in the energy region
10<SUP>14</SUP> to 10<SUP>17</SUP> eV (Bolivian Air Shower Joint
Experiment)
Authors: Toyoda, Y.; Suga, K.; Murakami, K.; Hasegawa, H.; Shibata,
S.; Domingo, V.; Escobar, I.; Kamata, K.; Bradt, H.; Clark, G.;
La Pointe, M.
1965ICRC....2..708T Altcode: 1965ICRC....9..708T
No abstract at ADS
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Title: The Primary energy spectrum from 8 x 10<SUP>14</SUP>-4 x
10<SUP>17</SUP> eV
Authors: Bradt, H.; Clark, G.; La Pointe, M.; Domingo, V.; Escobar,
I.; Kamata, K.; Murakami, K.; Suga, K.; Toyoda, Y.
1965ICRC....2..715B Altcode: 1965ICRC....9..715B
No abstract at ADS
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Title: Evidence for extensive air showers with extremely few
penetrating particles
Authors: Suga, K.; Escobar, I.; Murakami, K.; Domingo, V.; Toyoda,
Y.; Clark, G.; La Pointe, M.
1963ICRC....4....9S Altcode: 1963ICRC....8d...9S
No abstract at ADS
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Title: Primary energy spectrum from 6.10<SUP>14</SUP> ev to 4.10 ev
Authors: Clark, G.; Bradt, H.; La Pointe, M.; Domingo, V.; Escobar,
I.; Murakami, K.; Suga, K.; Toyoda, Y.; Hersil, J.
1963ICRC....4...65C Altcode: 1963ICRC....8d..65C
No abstract at ADS
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Title: Character of air showers at 5200 m altitude
Authors: Escobar, I.; Domingo, V.; Murakami, K.; Suga, K.; Toyoda,
Y.; Clark, G.; La Pointe, M.; Oda, M.; Bradt, H.; Miura, I.; Nagano,
M.; Shibata, S.; Tanahashi, G.; Hasegawa, H.
1963ICRC....4..168E Altcode: 1963ICRC....8d.168E
No abstract at ADS
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Title: A general account of the various research activities at
Chacaltaya
Authors: Domingo, V.
1963ICRC....4....3D Altcode: 1963ICRC....8d...3D
No abstract at ADS
