Phase-mixing of dust ion acoustic waves in plasmas

Abstract

We study the spatio-temporal evolution of low frequency dust ion acoustic waves (DIAWs) in collisionless plasmas containing hot Boltzmann-distributed electrons, cold inertial ions and cold negatively charged dust grains, taking the mobility of the dust grains into account. Our study reveals that DIAWs undergo phase-mixing for arbitrarily small initial amplitudes, causing them to suffer a gradual loss in wave coherency. A perturbative analysis of the governing equations leads us to conclude that the phase-mixing of DIAWs occur solely because of the dynamics of the dust grains. An estimate of the phase-mixing time is also obtained. It is observed to be greatly influenced by the values of certain plasma parameters, such as the dust density, the temperature of the electrons and the mass of the dust grains. We expect that the results of this investigation will be of relevance in laboratory as well as astrophysical plasma environments.