Numerical MHD Simulations of Solar Magnetoconvection and Oscillations in Inclined Magnetic Field Regions

TL;DR

This paper uses radiative MHD simulations to study how inclined magnetic fields in the solar penumbra affect oscillation frequencies, revealing significant shifts linked to fast MHD wave behavior.

Contribution

It provides new insights into the impact of magnetic field inclination on solar oscillation spectra using advanced numerical simulations.

Findings

Inclined magnetic fields cause a shift of resonance peaks to higher frequencies.

Frequency shifts are more pronounced in inclined fields than in vertical fields of similar strength.

Results are consistent with the behavior of fast MHD waves.

Abstract

The sunspot penumbra is a transition zone between the strong vertical magnetic field area (sunspot umbra) and the quiet Sun. The penumbra has a fine filamentary structure that is characterized by magnetic field lines inclined toward the surface. Numerical simulations of solar convection in inclined magnetic field regions have provided an explanation of the filamentary structure and the Evershed outflow in the penumbra. In this paper, we use radiative MHD simulations to investigate the influence of the magnetic field inclination on the power spectrum of vertical velocity oscillations. The results reveal a strong shift of the resonance mode peaks to higher frequencies in the case of a highly inclined magnetic field. The frequency shift for the inclined field is significantly greater than that in vertical field regions of similar strength. This is consistent with the behavior of fast MHD waves.