Excitation of MHD waves in magnetized anisotropic cosmologies

TL;DR

This paper investigates how magnetohydrodynamic waves are excited in anisotropic cosmological models with magnetic fields, revealing exponential growth of certain modes and the influence of resistivity and fluid instabilities.

Contribution

It introduces a study of MHD wave excitation in anisotropic cosmologies with magnetic fields, highlighting resistivity effects and instability enhancements.

Findings

Fast-magnetosonic modes grow exponentially and saturate at high values.

Resistivity enhances Jeans-like instabilities and condensation formation.

Magnetosonic wave growth is influenced by anisotropic fluid dynamics.

Abstract

The excitation of cosmological perturbations in an anisotropic cosmological model and in the presence of a homogeneous magnetic field was studied, using the resistive magnetohydrodynamic (MHD) equations. We have shown that fast-magnetosonic modes, propagating normal to the magnetic field grow exponentially and saturated at high values, due to the resistivity. We also demonstrate that the jeans-like instabilities are enhanced inside a resistive and the formation of condensations formed within an anisotropic fluid influence the growing magnetosonic waves.