A Theoretical Review of Diffusive Shock Acceleration

Abstract

We discuss the fundamental ideas of particle acceleration in plasma shocks with emphasis on those features that are required to produce the “universal” power-law spectrum. We compare shock acceleration with the more familiar second-order or stochastic acceleration and see that they are not too different in many respects. We discuss the features of shock acceleration that make it appealing and some of its problems as well. Subject headings: acceleration of particles — MHD — plasmas — shock waves