Electron Plasma Wave Shocks in a Collisionless Plasma

Abstract

A large-amplitude electron plasma wave in a bounded collisionless plasma is observed to steepen and form a shock with a trailing wave train. The dependence of the Mach number and the period of the wave train on the shock amplitude shows that the shock structure is related to solitary waves. For a larger-amplitude shock, however, the trailing wave train is small or disappears, and a potential jump followed by large-amplitude oscillations propagating with a slower velocity than that of the shock front is observed. The amplitude of the oscillations is sufficiently large to trap a significant number of electrons and to form vortices in phase space.