Standing MHD Waves in a Magnetic Slab Embedded in an Asymmetric Magnetic Plasma Environment: Surface Waves

TL;DR

This paper extends the analysis of standing MHD surface waves in magnetic slabs by including external magnetic fields, deriving frequency ratios and amplitude differences for potential solar magneto-seismology applications.

Contribution

The study generalizes previous models by incorporating external magnetic fields and derives analytical expressions for wave frequencies and amplitude differences in a weakly asymmetric, thin magnetic slab.

Findings

Frequency ratios of harmonics are derived analytically.

Amplitude differences across the slab are quantified.

Frequency is more sensitive to slab width than magnetic asymmetry.

Abstract

Building on a previous study that analyses surface waves in magnetic slabs embedded in a non-magnetic external environment, in this study the model is generalised and external magnetic fields are added. The slab is assumed to be thin, with weak magnetic asymmetry. The frequencies of the standing harmonic modes are derived to leading-order in the small quantities representing the thin slab width and the weak asymmetry. It is found that the frequencies are more prone to changes to the width of the slab than changes in the magnetic asymmetry. The frequency ratio of the first harmonic to the fundamental mode is derived, along with the amplitude difference between the two sides of the slab, as these may be observable quantities that can be compared with observational results and applied to carry out solar magneto-seismology.