Nonlinear structure in a current-carrying collisional dusty plasma

TL;DR

This paper investigates how perpendicular ion drift can generate magnetic field structures in highly collisional dusty plasmas, with applications to planetary rings, comets, and experiments, using a nonlinear PDE model.

Contribution

It introduces a nonlinear PDE model for magnetic field structures in collisional dusty plasmas driven by ion drift, analyzing stability and stationary states.

Findings

Identifies conditions for linear instability.

Describes periodic magnetic field arrangements.

Analyzes applications to planetary and cometary environments.

Abstract

A perpendicular ion drift is investigated as a mechanism for the generation of magnetic field structures in a highly collisional dusty plasma. The basic dissipation mechanism is assumed to be the dust-neutrals momentum exchange, so that plasmas with a small ionization fraction are natural candidates for experiments. The model reduces to a nonlinear partial differential equation for the vector potential. The conditions for linear instability are determined. The stationary states are periodic arrangements for the magnetic field, described by a Lienard equation. The fully depleted (ion-dust) case is also considered in detail. Applications to planetary rings, comets and dust acoustic instability experiments are analyzed. A necessary condition for the validity of the model is a sufficiently slow time-scale of the generated magnetic fields.