La mission solaire SOHO: quelques résultats récents

Abstract

After more than 3 years of operations, the SOHO solar mission has brought a large body of new results, the full exploitation of which continues. SOHO has provided evidence of the role of magnetic reconnection at many different spatial scales (including scales smaller than any spatial resolution) in direct heating by the Joule effect, or in generating MHD waves or accelerating particles. Reconnection seems to occur very low in the atmosphere with a permanent reshuffling of magnetic fields resulting from flux emergence at the borders of the supergranulation network. SOHO has also demonstrated the multifluid nature of the solar wind in the low corona where ion (and proton) temperatures are higher than electron temperatures. This ion heating can be explained by resonance between MHD waves and ion (and proton) gyration around the field lines. Such conclusions (and others) will be tested over the next few years with new observations from SOHO.