ELECTRON ACCELERATION AT QUASI-PARALLEL SHOCKS IN THE SOLAR CORONA AND ITS SIGNATURE IN SOLAR-TYPE-II RADIO-BURSTS

Recently, strong large amplitude magnetic field structures(SLAMS) have been observed as a common phenomenon in the vicinity of the quasi-parallel region of Earth's bow shock. A quasi-parallel shock transition can be considered as patchwork of SLAMS. Using the data of AMPTE/IRM magnetometer the properties of SLAMS are studied. Within SLAMS the magnetic field is strongly deformed and, thus, the magnetic field geometry is locally swung into a quasi-perpendicular regime. Therefore, electrons can locally be accelerated to high energies within SLAMS. Assuming that SLAMS also exist in the vicinity of supercritical, quasi-parallel shocks in the solar corona, they are able to generate radio radiation via the enhanced Langmuir turbulence excited by the accelerated electrons. Since SLAMS are connected with strong density enhancements, the aforementioned mechanism can explain the multiple-lane structure often occurred in solar Type II radio bursts.