Type II Solar Radio Bursts and Kappa Electron Distributions

摘要: Type II solar radio bursts involve a shock reflecting and accelerating ambient electrons back upstream, these electrons developing beam distribution functions unstable to the growth of Langmuir waves, generation of Langmuir waves, transformation of some Langmuir wave energy into radio emission near the electron plasma frequency and near , and propagation of the radio emission to observers. If the ambient electrons have Kappa distribution functions which appear power-law at high energies, rather than Maxwellians then the number of fast electrons (and so energy available) increases substantially and so does the level of the nonthermal ambient electron distribution function. In recent years we developed a quantitative theory for type II bursts that combines MHD simulations of a specific CME-driven shock with an analytic theory for the accelerated electrons, Langmuir waves, and radio emission. Here we present detailed …