Acoustic Power Absorption and its Relation with Vector Magnetic Field of a Sunspot

TL;DR

This study investigates how the vector magnetic field influences acoustic power absorption in sunspots, revealing that magnetic structures like spines affect absorption differently, with high-resolution Hinode data providing new insights.

Contribution

It utilizes high-resolution Hinode vector magnetograms to analyze the relationship between magnetic field structures and acoustic power absorption in sunspots, highlighting differences between spines and intra-spines.

Findings

Transverse magnetic fields peak at similar radial distances from sunspot centers.

Observed transverse fields are stronger than potential fields from SOHO/MDI.

Spines exhibit higher acoustic power absorption than intra-spines.

Abstract

The distribution of acoustic power over sunspots shows an enhanced absorption near the umbra--penumbra boundary. Earlier studies revealed that the region of enhanced absorption coincides with the region of strongest transverse potential field. The aim of this paper is to (i) utilize the high-resolution vector magnetograms derived using Hinode SOT/SP observations and study the relationship between the vector magnetic field and power absorption and (ii) study the variation of power absorption in sunspot penumbrae due to the presence of spine-like radial structures. It is found that (i) both potential and observed transverse fields peak at a similar radial distance from the center of the sunspot, and (ii) the magnitude of the transverse field, derived from Hinode observations, is much larger than the potential transverse field derived from SOHO/MDI longitudinal field observations. In the penumbra, the radial structures called spines (intra-spines) have stronger (weaker) field strength and are more vertical (horizontal). The absorption of acoustic power in the spine and intra-spine shows different behaviour with the absorption being larger in the spine as compared to the intra-spine.