Spectropolarimetrically accurate magnetohydrostatic sunspot model for forward modelling in helioseismology

TL;DR

This paper develops a spectropolarimetrically accurate magneto-hydrostatic sunspot model for helioseismology, enabling detailed simulations of wave interactions and radiative effects in sunspots to improve observational analysis.

Contribution

It introduces a novel technique to construct realistic sunspot models and simulates wave propagation and radiative transfer, advancing helioseismic forward modelling accuracy.

Findings

Confirmed increased acoustic power in sunspot umbrae away from disk center due to slow magneto-acoustic waves.

Demonstrated the influence of non-local radiative transport on helioseismic measurements.

Simulated multi-height observations revealing differences in acoustic power at various heights.

Abstract

We present a technique to construct a spectropolarimetrically accurate magneto-hydrostatic model of a large-scale solar magnetic field concentration, mimicking a sunspot. Using the constructed model we perform a simulation of acoustic wave propagation, conversion and absorption in the solar interior and photosphere with the sunspot embedded into it. With the $6173\mathrm{\AA}$ magnetically sensitive photospheric absorption line of neutral iron, we calculate observable quantities such as continuum intensities, Doppler velocities, as well as full Stokes vector for the simulation at various positions at the solar disk, and analyse the influence of non-locality of radiative transport in the solar photosphere on helioseismic measurements. Bisector shapes were used to perform multi-height observations. The differences in acoustic power at different heights within the line formation region at different positions at the solar disk were simulated and characterised. An increase in acoustic power in the simulated observations of the sunspot umbra away from the solar disk centre was confirmed as the slow magneto-acoustic wave.