Modulation of waves due to charge-exchange collisions in magnetized partially ionized space plasma

TL;DR

This paper presents a nonlinear fluid simulation model that explores how magnetohydrodynamic waves in partially ionized space plasma are modulated by charge-exchange collisions, revealing robust wave growth and damping behaviors.

Contribution

The study introduces a self-consistent MHD-neutral fluid model that captures nonlinear wave modulation due to charge-exchange collisions in partially ionized plasma.

Findings

Alfvénic and fast/slow modes exhibit alternating growth and damping.

Wave modulation persists despite strong neutral damping.

The model demonstrates nonlinear wave behavior in space plasma conditions.

Abstract

A nonlinear time dependent fluid simulation model is developed that describes the evolution of magnetohydrodynamic waves in the presence of collisional and charge exchange interactions of a partially ionized plasma. The partially ionized plasma consists of electrons, ions and a significant number of neutral atoms. In our model, the electrons and ions are described by a single fluid compressible magnetohydrodynamic (MHD) model and are coupled self-consistently to the neutral gas, described by the compressible hydrodynamic equations. Both the plasma and neutral fluids are treated with different energy equations that describe thermal energy exchange processes between them. Based on our self-consistent model, we find that propagating Alfv\'enic and fast/slow modes grow and damp alternately through a nonlinear modulation process. The modulation appears to be robust and survives strong damping by the neutral component.