Longitudinal Plasma Motions Generated by Shear Alfv\'en Waves in Plasma with Thermal Misbalance

TL;DR

This paper investigates how thermal misbalance caused by shear Alfvén waves influences longitudinal plasma motions, revealing exponential bulk flows and frequency-dependent amplitude and phase shifts, with analytical and numerical analysis in coronal conditions.

Contribution

It introduces a model linking thermal misbalance to Alfvén wave-induced plasma motions, including analytical and numerical analysis of their evolution under coronal conditions.

Findings

Thermal misbalance causes exponential bulk flows in plasma.

Amplitude and phase of longitudinal motions depend on Alfvén wave frequency.

Numerical results agree with analytical predictions.

Abstract

Compressional plasma perturbations may cause thermal misbalance between plasma heating and cooling processes. This misbalance significantly affects the dispersion properties of compressional waves providing a feedback between the perturbations and plasmas. It has been shown that Alfv\'en waves may induce longitudinal (compressional) plasma motions. In the present study, we analyze the effects of thermal misbalance caused by longitudinal plasma motions induced by shear Alfv\'en waves. We show that thermal misbalance leads to appearance of exponential bulk flows, which itself modifies the Alfv\'en induced plasma motions. In the case of sinusoidal Alfv\'en waves, we show how the amplitude and phase shift of induced longitudinal motions gain dependence on the Alfv\'en wave frequency while shedding light on its functionality. This feature has been investigated analytically in application to coronal conditions. We also consider the evolution of longitudinal plasma motions induced by the shear sinusoidal Alfv\'en wave by numerical methods before comparing the results obtained with our presented analytical predictions to justify the model under consideration in the present study.