Phase mixing due to ion motion and relativistic effects in nonlinear plasma oscillations

Abstract

Nonlinear electron plasma oscillations in a cold-plasma have been studied numerically using one-dimensional (1D) Vlasov–Poisson equations. It is shown that both ion motion and the relativistic effect of electron motion can lead to phase mixing phenomena even if a plasma oscillation is at a moderate amplitude. When its amplitude is relatively small, the phase mixing is mainly caused by the ion motion. When its amplitude is large, the relativistic effect of electrons is dominant. The nonlinear process caused by the relativistic effect depends significantly upon the phase velocity of the plasma oscillation, while that caused by the ion motion depends weakly upon its phase velocity.