Fast magnetic wave could heat the solar low-beta chromosphere

TL;DR

This study uses 2D radiative MHD simulations to demonstrate that fast magnetic waves play a significant role in heating the low-beta chromosphere through mode conversion from acoustic waves.

Contribution

It provides the first quantitative analysis showing the importance of fast magnetic waves in chromospheric heating via mode conversion mechanisms.

Findings

Fast magnetic waves significantly heat the low-beta chromosphere.

Mode conversion from acoustic to magnetic waves is efficient at large attack angles.

Simulations quantify the heating rate from shock wave entropy jumps.

Abstract

Magnetohydrodynamic (MHD) waves are candidates for heating the solar chromosphere, although it is still unclear which mode of the wave is dominant in heating. We perform two-dimensional radiative MHD simulation to investigate the propagation of MHD waves in the quiet region of the solar chromosphere. We identify the mode of the shock waves by using the relationship between gas pressure and magnetic pressure across the shock front and calculate their corresponding heating rate through the entropy jump to obtain a quantitative understanding of the wave heating process in the chromosphere. Our result shows that the fast magnetic wave is significant in heating the low-beta chromosphere. The low-beta fast magnetic waves are generated from high-beta fast acoustic waves via mode conversion crossing the equipartition layer. Efficient mode conversion is achieved by large attacking angles between the propagation direction of the shock waves and the chromospheric magnetic field.