Regensburg 2007 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 7: Solar-Terrestrische Beziehungen

EP 7.8: Vortrag

Dienstag, 27. März 2007, 18:15–18:30, H46

Electron acceleration by the reconnection outflow shock during solar flares — •Gottfried Mann — Astrophysikalisches Institut Potsdam, An der Sternwarte 16, D-14482 Potsdam

During solar flares a large amount of nonthermal electromagnetic radiation up to the γ−ray range is emitted from the corona implying the generation of energetic electrons. Within the framework of the magnetic reconnection scenario, jets appear in the outflow region and can establish standing fast-mode shocks if they penetrate with a super-Alfvénic speed into the surrounding plasma. These shocks can be a source of energetic electrons. During the solar event on October 28, 2003 an enhanced flux of hard X− and γ−rays up to an energy of 10 MeV has been observed by the INTEGRAL spacecraft indicating the generation of relativistic electrons. The radio signature of a standing shock wave appeared simultaneously with the enhanced hard X− and γ−ray fluxes. Here, this shock is assumed to be the source of the highly energetic electrons needed for the hard X− and γ−ray as well as the nonthermal radio radiation. The electrons are energized by shock drift acceleration, which is necessarily treated in a fully relativistic manner. After acceleration, the electrons travel along the magnetic field lines towards the denser chromosphere, where they emit hard X− and γ−ray radiation via bremsstrahlung.