Theory and Simulations of Whistler Wave Propagation

TL;DR

This paper develops a linear theory for whistler wave propagation using electron magnetohydrodynamics, providing analytic solutions and simulations that match experimental observations, and explores nonlinear effects governed by the Hall force.

Contribution

It introduces a comprehensive linear theory and simulations for whistler waves within electron MHD, including exact solutions and nonlinear regime analysis.

Findings

Wave solutions match observed magnetic structures.

Parallel group velocity exceeds perpendicular velocity.

Nonlinear evolution driven by Hall force.

Abstract

A linear theory of whistler wave is developed wihtin the paradigm of a two dimensional incompressible electron magnetohydrodynamics model. Exact analytic wave solutions are obtained for a small amplitude whistler wave that exhibit magnetic field topological structures consistent with the observations and our simulations in linear regime. In agreement with experiment, we find that the parallel group velocity of the wave is large compared to its perpendicular counterpart. Numerical simulations of collisional interactions demonstrate that the wave magnetic field either coalesces or repels depending upon the polarity of the associated current. In the nonlinear regime, our simulations demonstrate that the evolution of wave magnetic field is governed essentially by the nonlinear Hall force.