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Etude de la couronne solaire en 3D et de son évolution avec SOHO/EIT

Abstract : This thesis deals with 3D evolution of coronal structures based upon the ultraviolet telescope of SOHO : EIT.
Anaglyphs and incertainties on a complete stereovision reconstruction are described.
Stereoscopic methods for loop reconstruction were successfully made to find 3D parameters. With dynamical stereoscopy, physical conditions were derived for 30 loops of temperature around 1MK.
A method which is able to derive twist variation were also built. Emerging loops were found highly twisted and they detwist as they grow. According to helicity conservation, this correspond to a transfert of twist into expansion.
Long time twist evolution of magnetic flux tubes are followed in relation with flares as relaxation.
Interaction between magnetic field lines were analysed. An example of reconnection
between open and closed field line were observed. Other interactions were found with
multi-wavelength observations : coronal holes borders (and thus CH) are better defined when an active region nearby is growing.
Other imaging techniques were used to better take profit as possible of SOHO/EIT.
A multiscale vision model (MVM) was applied with success to show small coronal structures evolutions hidden by the noise level.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00089354
Contributor : Fabrice Portier-Fozzani <>
Submitted on : Thursday, August 17, 2006 - 5:09:20 PM
Last modification on : Thursday, July 25, 2019 - 4:34:13 PM
Long-term archiving on: : Monday, April 5, 2010 - 11:07:23 PM

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  • HAL Id : tel-00089354, version 1

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Fabrice Portier-Fozzani. Etude de la couronne solaire en 3D et de son évolution avec SOHO/EIT. Astrophysique [astro-ph]. Université Nice Sophia Antipolis, 1999. Français. ⟨tel-00089354⟩

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