On the parallel and oblique firehose instability in fluid models

Abstract

A brief analysis of the proton parallel and oblique firehose instability is presented from a fluid perspective and the results are compared to kinetic theory solutions obtained by the WHAMP code. It is shown that the classical CGL model very accurately describes the growth rate of these instabilities at sufficiently long spatial scales (small wavenumbers). The required stabilization of these instabilities at small spatial scales (high wavenumbers) naturally requires dispersive effects and the stabilization is due to the Hall term and finite Larmor radius (FLR) corrections to the pressure tensor. Even though the stabilization is not completely accurate since at small spatial scales a relatively strong collisionless damping comes into effect, we find that the main concepts of the maximum growth rate and the stabilization of these instabilities is indeed present in the fluid description. However, there are differences that are quite pronounced when close to the firehose threshold and that clarify the different profiles for marginally stable states with a prescribed maximum growth rate ${\gamma }_{max}$ in the simple fluid models considered here and the kinetic description.

References in corpus (3)

• Predicted Impacts of Proton Temperature Anisotropy on Solar Wind Turbulence
• Pressure-anisotropy-driven microturbulence and magnetic-field evolution in shearing, collisionless plasma
• Plasma turbulence and kinetic instabilities at ion scales in the expanding solar wind

Cited by in corpus (13)

• The multi-scale nature of the solar wind
• An introductory guide to fluid models with anisotropic temperatures Part 1 -- CGL description and collisionless fluid hierarchy
• The parametric instability of Alfvén waves: effects of temperature anisotropy
• Amplitude limits and nonlinear damping of shear-Alfvén waves in high-beta low-collisionality plasmas
• New closures for more precise modeling of Landau damping in the fluid framework
• Generalized Fluid Models of the Braginskii Type
• Nonlinear firehose relaxation and constant-B field fluctuations
• A new low-beta regime for unstable proton firehose modes in bi-Kappa distributed plasmas
• Particle-In-Cell simulations of the parallel proton firehose instability influenced by the electron temperature anisotropy in solar wind conditions
• Action Principles and Conservation Laws for Chew-Goldberger-Low Anisotropic Plasmas
• Fire-hose instability of inhomogeneous plasma flows with heat fluxes
• Critical comparison of collisionless fluid models: Nonlinear simulations of parallel firehose instability
• Impact of pressure anisotropy on the cascade rate of Hall-MHD turbulence with biadiabatic ions