John T. Gosling
   Los Alamos National Laboratory, Los Alamos, New Mexico, USA

Gross distortions of ion and electron velocity distributions occur as solar wind plasma encounters a collisionless shock. These distortions are produced by macroscopic electric and magnetic fields within the shock layer and are of fundamental importance in initiating the heating and acceleration process for both ions and electrons at such shocks. The very nature of a collisionless shock depends importantly on such things as the orientation of the upstream magnetic field and the Mach number of the shock. Here we review kinetic aspects of collisionless shocks in the solar wind, with emphasis on the suprathermal ion and electron populations they produce.