Heidelberg 2006 – scientific programme

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EP: Extraterrestrische Physik

EP 17: Sonne: Atmosph
äre

EP 17.1: Invited Talk

Thursday, March 16, 2006, 09:00–09:30, B

Special Results from the RHESSI-Mission — •Gottfried Mann — Astrophysikalisches Institut Potsdam, An der Sternwarte 16, D-14482 Potsdam

RHESSI (Ramaty High Energy Solar Spectroscopic Imager) was launched in the framework of the Small Explorer program by NASA on February 5, 2002. The spectrometer covering the range 3 keV - 17 MeV consists of 9 cooled Germanium crystals. Thus, RHESSI is providing hard X-ray images of the Sun with an unprecedented spectral and spatial resolution for three years.

The main aim of this mission is to get more information on electron acceleration during solar flares. Since energetic electrons are responsible for both the nonthermal radio and X-ray radiation, the Astrophysical Institute Potsdam participates in the RHESSI mission by a common radio and RHESSI data analysis using its own radio data, which are provided by the radiospectralpolarimeter (40-800 MHz).

A special mechanism for generation of highly energetic electrons will be presented. Magnetic reconnection is thought to be the basic process during flares. According to this scenario high speed jets are pushed away from the reconnection site. If the velocity of such jets is super-Alfvenic, then a shock wave can be established in the outflow region of reconnection. This shock is able to generate highly energetic electrons, which can be the source of hard X-ray radiation. This mechanism will be discussed in a quantitative manner and compared with radio and RHESSI data.