Identifying magnetohydrodynamic wave modes in the solar atmosphere: Experiments in 2D

¹ Rosseland Centre for Solar Physics, University of Oslo, PO Box 1029 Blindern, NO-0315 Oslo, Norway
² Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, NO-0315 Oslo, Norway
³ School of Mathematics and Statistics, University of St Andrews, St Andrews, Fife KY16 9SS, UK

^⋆ Corresponding author.

Received: 21 February 2025
Accepted: 11 June 2025

Abstract

Context. Magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. They are thought to play an important role in maintaining the temperature of the solar corona and are important components of coronal seismology. However, research into reliable wave mode identification schemes is still in its early stages. Such a scheme would be a valuable tool for understanding the role of waves in the coronal heating problem. A widely renowned 2003 study in 2D on magnetoacoustic gravity (MAG) waves crossing the β = 1 layer in the atmosphere provided valuable insights into wave propagation, from the lower to the upper atmosphere. The in-depth analyses of wave propagation through the solar atmosphere offer a valuable reference, which can be used to test other wave mode identifier schemes that could subsequently be expanded to 3D.

Aims. We aim to analyse a set of wave mode identification components designed to isolate properties of fast and slow MAG waves.

Methods. We recreated the 2003 experiment using the numerical code Bifrost with simplified boundary conditions. We then compared the existing wave analysis to our own scheme.

Results. We show that our wave mode identification scheme is equivalent to that of the scheme used in the 2003 study. We show how physical properties such as steepening, maximum, and minimum can be deduced from the scheme. As these wave mode identifiers can be expanded to 3D, the recreation of the piston experiment along with the careful analysis of the components opens the door for further studies into how MAG waves are transmitted across the β = 1 layer.