Numerical study of a dust-contaminated electron plasma

Abstract

The collective behaviour of dusty plasmas is heavily affected by the presence of a small fraction of micrometric or sub-micrometric dust particles which collect a large surface charge. While dusty plasmas under study are usually quasi-neutral, we propose here an investigation on a magnetized nonneutral plasma (a situation found for example in Penning traps) where a conventional plasma with a single sign of charge (e.g. electrons) is contaminated by a dust population. We simulate the two-dimensional dynamics of such a plasma in the plane orthogonal to a homogeneous magnetic field with a tailored Particle-In-Cell code implementing a mass-less fluid (drift-Poisson) approximation for electrons and a kinetic description for the dust component, including gravity effects. Simulations with a range of initial conditions are performed to observe the influence of dust on the diocotron instability developing in the electron plasma. The early stage of the growth of diocotron modes is analyzed by Fourier decomposition. The fully non-linear evolution is studied by means of a statistical analysis of probability density functions and flatness of spatial vorticity increments in order to characterize the intermittency properties of the turbulence.