Effect of Trapped Particles on the Nonlinear Evolution of a Wave Packet

Abstract

We present numerical simulations of the evolution of a large-amplitude electrostatic wave packet in a hot collisionless plasma. When resonant particles are trapped by the wave potential during a transit time, the number of lobes in the packet is observed to increase. This is explained in terms of an equation of propagation for the packet amplitude and a dispersion relation involving the trapped particles.