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Accueil > Séminaires & Soutenances > Séminaires, soutenances de thèses et HDR précédents > 2012 > Séminaires 2012 > Le jeudi 16 février à 14h

Le jeudi 16 février à 14h

Judith De Patoul (Max Planck Institute for Solar System Research)

Salle de réunion à Saint-Maur.

2-D and 3-D solar polar plume analysis from the three vantage positions of STEREO A, B and SoHO spacecraft.

Abstract : The hot solar corona consists of a low density plasma, which is highly structured by the magnetic field. EUV (Extreme Ultraviolet) image sequences of the lower solar corona have revealed a wide variety of structures with sizes ranging from the Sun’s diameter to the limit of the angular resolution. We analyze solar polar plume structures which appear in EUV images as elongated objects starting on the surface of the Sun extending super-radially into the corona. Their formation and contribution to the fast solar wind and other coronal phenomena are still under debate. Knowledge of the polar plume 3D geometry helps to understand some of the physical processes within the solar corona. Firstly, we automatically identify plumes in solar EUV images from a sequence of images taken simultaneously by the three spacecraft telescopes STEREO/EUVI A and B, and SoHO/EIT. This plume identification method is based on a multiscale Hough-wavelet analysis. Then we determine their 3D localizations and geometries using tomography techniques including the differential rotation of the sun and, using conventional stereoscopic triangulation. Finally, we analyzed and discussed the shape and size of their cross sections as well as the temporal evolution of the mean orientation of plumes from May 2007 to April 2008.

CNRS Ecole Polytechnique Sorbonne Université Université Paris-Saclay Observatoire de Paris
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Exploitant du site : Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay F-91128 PALAISEAU CEDEX
Hébergeur : Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay F-91128 PALAISEAU CEDEX
Directeur de la publication : Dominique Fontaine (Directrice)