Solar type II radio emission and the shock drift acceleration of electrons

Many of the properties of energetic electrons and ions accelerated by interplanetary shock waves can be understood in terms of the shock drift acceleration mechanism. In this paper we show that the shock drift acceleration of electrons can be responsible for solar type II radio bursts as well. We review the shock drift acceleration mechanism and show that the streaming distribution of reflected electrons produced upstream of the shock front by this mechanism can be unstable to the generation of electrostatic plasma waves, which in turn interact to produce the observed radio emission. We derive constraints upon the density and energy of suprathermal electrons required to produce a typical type II burst