| During solar flares a large amount of energy is suddenly released and partly transfered into
energetic electrons. They are of special interest since a substantial part of the energy released
during a flare is deposited into the energetic electrons. They can be observed as an enhanced
emission of nonthermal radio and X-ray radiation. RHESSI observations, e.g. of the
solar event on October 28, 2003, show that 1036 electrons with energies >Â 20Â keV
are typically produced per second during large flares. They are related to a power
of about 1029Â W. It is a still open question in which way so much electrons are
accelerated up to high energies during a fraction of a second. 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. It is the aim to show that this shock can be the source of
the energetic electrons produced during flares. The electrons are regarded to be
energized by shock drift acceleration. The process is necessarily treated in a fully
relativistic manner. The resulting distribution function of accelerated electrons is a
loss-cone one and allows to calculated the differential electron flux, which can be
compared with RHESSI. The theoretically obtained fluxes of energetic electrons
agree with the observed ones as demonstrated for the solar event on October 28,
2003. |