Physical Properties of Wave Motion in Inclined Magnetic Fields Within Sunspot Penumbrae

TL;DR

This study investigates how inclined magnetic fields in sunspot penumbrae influence acoustic wave motion, revealing elliptical wave behavior and phase shift variations related to magnetic field inclination.

Contribution

It introduces a model linking elliptical wave motion to magnetic field inclination and demonstrates phase shift differences in varying magnetic field strengths.

Findings

Elliptical wave motion is influenced by magnetic field inclination.

Phase shifts differ between inward and outward propagating waves based on field strength.

Inclined magnetic fields alter acoustic wave properties in sunspot penumbrae.

Abstract

At the surface of the Sun, acoustic waves appear to be affected by the presence of strong magnetic fields in active regions. We explore the possibility that the inclined magnetic field in sunspot penumbrae may convert primarily vertically propagating acoustic waves into elliptical motion. We use helioseismic holography to measure the modulus and phase of the correlation between incoming acoustic waves and the local surface motion within two sunspots. These correlations are modeled assuming the surface motion is elliptical, and we explore the properties of the elliptical motion on the magnetic field inclination. We also demonstrate that the phase shift of the outward propagating waves is opposite to the phase shift of the inward propagating waves in stronger, more vertical fields, but similar to the inward phase shifts in weaker, more inclined fields.