Reduction of compressibility and parallel transfer by Landau damping in turbulent magnetized plasmas

TL;DR

This study uses advanced fluid simulations to show that Landau damping significantly reduces compressibility and parallel energy transfer in turbulent magnetized plasmas, aligning with kinetic theory and improving turbulence modeling.

Contribution

The paper introduces a FLR-Landau fluid model that incorporates Landau damping and FLR effects, accurately capturing turbulence behavior in collisionless plasmas unlike traditional Hall-MHD models.

Findings

Landau damping causes significant magnetosonic wave damping.

Compressibility and parallel energy cascade are inhibited at moderate beta.

The model better describes turbulence in collisionless plasmas like the solar wind.

Abstract

Three-dimensional numerical simulations of decaying turbulence in a magnetized plasma are performed using a so-called FLR-Landau fluid model which incorporates linear Landau damping and finite Larmor radius (FLR) corrections. It is shown that compared to simulations of compressible Hall-MHD, linear Landau damping is responsible for significant damping of magnetosonic waves, which is consistent with the linear kinetic theory. Compressibility of the fluid and parallel energy cascade along the ambient magnetic field are also significantly inhibited when the beta parameter is not too small. In contrast with Hall-MHD, the FLR-Landau fluid model can therefore correctly describe turbulence in collisionless plasmas such as the solar wind, providing an interpretation for its nearly incompressible behavior.