Nonlinear Evolution of the Dust Acoustic Instability in Artificially Created Dusty Space Plasmas

Abstract

A 2-D hybrid electrostatic model is used to investigate the dust acoustic instability driven by an ion beam. To understand the generation and the nonlinear electrostatic waves, we investigate possible parameter regimes for the dust acoustic instability. The principal application involves the Charged Aerosol Release Experiment in the ionosphere, but also potential applications are for the planetary ring system of Saturn. The plasma background ions and charged dust are treated as discrete particles, whereas electrons are dealt with as a Boltzmann fluid. A Monte Carlo collision model is adopted to deal with the ion-neutral collisions. The kinetic dispersion relation is numerically solved to investigate effects of the ion drift velocity and the dust charge and density on the wave growth rate and the wave propagation direction. The simulation results agree with linear analysis of the instability, which also shows that the most unstable dust acoustic wave may obliquely propagate to the streaming direction. This may be important for radar diagnostics. The wave saturates by trapping dust. The waves damp out as the ion-neutral collision frequency increases comparable with the wave growth rate, and more importantly, such collision may lead to unstable waves propagating even further off the streaming direction.