Ion motion can cause nonlinear electron acoustic waves in plasmas to phase-mix: A theoretical study

Theoretical investigation on the space-time evolution of standing electron acoustic waves (EAWs) reveals the collisionless damping of these modes as they slowly lose phase-coherency because of phase-mixing. Finite ion inertia is the responsible factor behind phase-mixing of EAWs in an electron–ion plasma with hot and cold electrons. A simple perturbation analysis of the fluid-Maxwell's equations shows that phase-mixing can happen at arbitrary amplitudes. Our analysis also predicts the approximate time of phase-mixing. It is found that a larger proportion of the hot electrons increases the phase-mixing time, while on the other hand, a higher temperature of hot electrons decreases it. The findings of this article might be relevant to comprehend different nonlinear phenomena of space and laboratory plasmas.