Wave instabilities in an anisotropic magnetized space plasma

TL;DR

This paper investigates wave instabilities in anisotropic, collisionless space plasmas like the solar wind, revealing a more complex wave spectrum with both stable and unstable modes due to anisotropic thermal fluxes.

Contribution

It introduces a new analysis using 16-moment equations, showing a richer wave spectrum than traditional models based on 13-moment equations.

Findings

Discovery of a more complex wave spectrum with stable and unstable modes.

Derivation of a general dispersion relation for incompressible wave modes.

Identification of differences from classic fire-hose instability models.

Abstract

We study wave instability in an collisionless, rarefied hot plasma (e.g. solar wind or corona). We consider the anisotropy produced by the magnetic field, when the thermal gas pressures across and along the field become unequal. We apply the 16-moment transport equations (obtained from the Boltzmann-Vlasov kinetic equation) including the anisotropic thermal fluxes. The general dispersion relation for the incompressible wave modes is derived. It is shown that a new, more complex wave spectrum with stable and unstable behavior is possible, in contrast to the classic fire-hose modes obtained in terms of the 13-moment integrated equations.