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Sylvaine Turck-chièze - One of the best experts on this subject based on the ideXlab platform.
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How the solar dynamics can influence the Sun–Earth medium term relationship
Journal of Atmospheric and Solar-Terrestrial Physics, 2011Co-Authors: Sylvaine Turck-chièze, Sandrine LefebvreAbstract:International audienceWe recall how the Sun is introduced in the present climatic models and discuss why the solar standard model (SSM) framework is insufficient to describe the Sun-Earth medium term relationship. We then report on the different sources of variability. The SOHO Mission allows a comparison between two successive solar minima and puts new constraints on the internal rotation profile. The coming space Missions SDO and PICARD will add crucial information on internal circulations and on the superficial asphericity. The interplay between the solar dynamics and terrestrial atmospheric models is in its infancy, it calls for medium term uninterrupted solar observations which will take benefit of a formation flying concept
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How the solar dynamics can influence the Sun-Earth medium term relationship
Journal of Atmospheric and Solar-Terrestrial Physics, 2011Co-Authors: Sylvaine Turck-chièze, Sandrine LefebvreAbstract:We recall how the Sun is introduced in the present climatic models and discuss why the solar standard model (SSM) framework is insufficient to describe the Sun-Earth medium term relationship. We then report on the different sources of variability. The SOHO Mission allows a comparison between two successive solar minima and puts new constraints on the internal rotation profile. The coming space Missions SDO and PICARD will add crucial information on internal circulations and on the superficial asphericity. The interplay between the solar dynamics and terrestrial atmospheric models is in its infancy, it calls for medium term uninterrupted solar observations which will take benefit of a formation flying concept.
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How the solar dynamics can influence the Sun–Earth medium term relationship
Journal of Atmospheric and Solar-Terrestrial Physics, 2010Co-Authors: Sylvaine Turck-chièze, Sandrine LefebvreAbstract:We recall how the Sun is introduced in the present climatic models and discuss why the solar standard model (SSM) framework is insufficient to describe the Sun-Earth medium term relationship. We then report on the different sources of variability. The SOHO Mission allows a comparison between two successive solar minima and puts new constraints on the internal rotation profile. The coming space Missions SDO and PICARD will add crucial information on internal circulations and on the superficial asphericity. The interplay between the solar dynamics and terrestrial atmospheric models is in its infancy, it calls for medium term uninterrupted solar observations which will take benefit of a formation flying concept.
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The Dynamics perspective including the observation of the deep solar magnetism
EAS Publications Series, 2009Co-Authors: Sylvaine Turck-chièzeAbstract:The stellar internal magnetism is presently poorly known, even we have now some evidence that it plays a crucial role in different stages of stellar evolution. I first recall the helioseismic results coming from the SOHO Mission on the deep interior. Then I show how we hope to observe directly or indirectly the deep solar magnetism by the simultaneous detection of gravity modes, acoustic modes and other phenomena. The two following sections compare the different techniques of observation and show the interest of a multichannel resonant spectrometer both for studying the deep dynamics of the core and for putting some constraints on the stellar atmospheric models. The last section describes the DynaMICCS Mission submitted to ESA in the framework of Cosmic Vision 2015–2025 and the observations of the coming decade with the GOLF–NG instrument dedicated to the magnetism of the core and to the region located between photosphere and chromosphere.
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Probing the internal solar magnetic field through g-modes
Monthly Notices of the Royal Astronomical Society, 2007Co-Authors: T. I. Rashba, Sylvaine Turck-chièze, Victor B. Semikoz, José W. F. ValleAbstract:The observation of g-mode candidates by the SOHO Mission opens the possibility of probing the internal structure of the solar radiative zone (RZ) and the solar core more directly than possible via the use of the p-mode helioseismology data. We study the effect of rotation and RZ magnetic fields on g-mode frequencies. Using a self-consistent static MHD magnetic field model we show that a 1% g-mode frequency shift with respect to the Solar Seismic Model (SSeM) prediction, currently hinted in the GOLF data, can be obtained for magnetic fields as low as 300 kG, for current measured modes of radial order n=-20. On the other hand, we also argue that a similar shift for the case of the low order g-mode candidate (l=2, n=-3) frequencies can not result from rotation effects nor from central magnetic fields, unless these exceed 8 MG.
B. Fleck - One of the best experts on this subject based on the ideXlab platform.
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Major Scientific Results from SOHO on Coronal Mass Ejections
2016Co-Authors: N. Gopalswamy, B. Fleck, J. B. GurmanAbstract:Abstract: Major scientific results related to coronal mass ejections (CMEs) observed by the Solar and heliospheric Observatory (SOHO) Mission are discussed. After a brief description of the general properties of CMEs, their relationship to geomagnetic storms, solar energetic particles, and radio bursts is discussed. Also discussed are the CME-driven shocks and their interaction with other CMEs. 1
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First Results from SOHO.
Astrophysics and Space Science, 1997Co-Authors: B. FleckAbstract: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 by the solar wind. This paper reports some of the first results from the SOHO Mission.
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The SOHO Mission: An overview
Solar Physics, 1995Co-Authors: V. Domingo, B. Fleck, A. I. PolandAbstract: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).
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the SOHO Mission
Solar Physics, 1995Co-Authors: B. FleckAbstract:SOHO, the Solar and Heliospheric Observatory, 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. In this paper a Mission overview is given, comprising scientific objectives, payload, spacecraft, operations, and data and ground system.
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The scientific payload of the space-based Solar and Heliospheric Observatory (SOHO)
Space Science Reviews, 1994Co-Authors: V. Domingo, B. Fleck, A. I. PolandAbstract: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.
A. I. Poland - One of the best experts on this subject based on the ideXlab platform.
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The SOHO Mission: An overview
Solar Physics, 1995Co-Authors: V. Domingo, B. Fleck, A. I. PolandAbstract: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).
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The scientific payload of the space-based Solar and Heliospheric Observatory (SOHO)
Space Science Reviews, 1994Co-Authors: V. Domingo, B. Fleck, A. I. PolandAbstract: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.
Jean-francois Hochedez - One of the best experts on this subject based on the ideXlab platform.
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Segmentation of Extreme Ultraviolet Solar Images using a Multispectral Data Fusion Process
2007 IEEE International Fuzzy Systems Conference, 2007Co-Authors: Vincent Barra, Veronique Delouille, Jean-francois HochedezAbstract:Accurate means of quantifying the respective contributions of different structures to the solar irradiance is now a key issue in Solar Physics, with implications to Sun-Earth relationships and space weather study. In this paper, we propose a three-step fusion scheme, that allows to aggregate (17.1 nm, 19.5 nm) data stemming from the solar EIT instrument onboard the SOHO Mission, and that is flexible enough to allow the integration of other type of information. The method is based on both a spatially constrained possibilistic clustering algorithm and a context dependent fusion operator. It aggregates the complementary and redundant information coming from the input sources. The results obtained on a 9-year dataset are consistent with those found in the solar physics literature. Unlike previous algorithms used in solar physics, our method has the ability to add further heterogeneous sources and sensors (e.g. human knowledge, images in other bandpasses, ratio of images) to the process, in order to postpone the decision step (here the segmentation of structures of interest) until sufficient information is available.
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Long-term variations in the Extreme-UV corona: the EIT/SOHO perspective
Symposium - International Astronomical Union, 2001Co-Authors: Jean-francois Hochedez, Frédéric Clette, Erwin Verwichte, David Berghmans, P. CugnonAbstract:Since the start of the SOHO Mission, EIT -the Extreme ultraviolet Imaging Telescope- offers a global view of the solar corona over the whole rising phase of the current activity cycle. Such a dataset is unprecedented. We give here the current results of an on-going investigation over the entire EIT archive. In the Fe XV images (2 MK), the on-disk and off-disk intensity distributions have been evaluated, and their evolution is described. Additionally, we developed an image processing technique that extracts the smallest detectable features. The cosmic ray hits are statistically disentangled from the solar point-like phenomena, and the trends in both rates are assessed.
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EIT: Extreme-UltraViolet Imaging Telescope for the SOHO Mission
Solar Physics, 1995Co-Authors: Jean-pierre Delaboudiniere, Jean-francois Hochedez, G. E. Artzner, J. Brunaud, A. H. Gabriel, F. Millier, X. Y. Song, Kenneth P. Dere, Russell A. HowardAbstract:The Extreme-ultraviolet Imaging Telescope (EIT) will provide wide-field images of the corona and transition region on the solar disc and up to 1.5 R⊙ above the solar limb. Its normal incidence multilayer-coated optics will select spectral eMission lines from Fe IX (171 A), Fe XII (195 A), Fe XV (284 A), and He II (304 A) to provide sensitive temperature diagnostics in the range from 6 × 104 K to 3 × 10 6 K. The telescope has a 45×45 arcmin field of view and 2.6 arcsec pixels which will provide approximately 5-arcsec spatial resolution. The EIT will probe the coronal plasma on a global scale, as well as the underlying cooler and turbulent atmosphere, providing the basis for comparative analyses with observations from both the ground and other SOHO instruments. This paper presents details of the EIT instrumentation, its performance and operating modes.
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Calibration of the EIT instrument for the SOHO Mission
X-Ray and EUV FUV Spectroscopy and Polarimetry, 1995Co-Authors: Jean-marc Defise, Jean-francois Hochedez, Xueyan Song, Jean-pierre Delaboudiniere, G. E. Artzner, C. Carabetian, J. Brunaud, J. Daniel Moses, R. C. Catura, Frédéric CletteAbstract:Optical characteristics in the wavelength range 15 - 75 nm of the EUV imaging telescope to be launched soon on the SOHO Mission are discussed. Bandpasses and photometric sensitivity of the multilayered optics telescope have been measured by a dedicated synchrotron light source at Orsay, France.
V. Domingo - One of the best experts on this subject based on the ideXlab platform.
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The SOHO Mission: An overview
Solar Physics, 1995Co-Authors: V. Domingo, B. Fleck, A. I. PolandAbstract: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).
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SOHO: The Solar and Heliospheric Observatory
The High Latitude Heliosphere, 1995Co-Authors: V. Domingo, Bernhard Fleck, Arthur I. PolandAbstract: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.
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The scientific payload of the space-based Solar and Heliospheric Observatory (SOHO)
Space Science Reviews, 1994Co-Authors: V. Domingo, B. Fleck, A. I. PolandAbstract: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.
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SOHO Science Opportunities
International Astronomical Union Colloquium, 1994Co-Authors: Bernhard Fleck, V. Domingo, Arthur I. PolandAbstract:AbstractThe 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.
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SOHO: Science Objectives and Capabilities
Solar Surface Magnetism, 1994Co-Authors: Bernhard Fleck, V. Domingo, Arthur I. PolandAbstract: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 to reach 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.