Numerical simulation of the interaction between solar granules and small-scale magnetic fields

TL;DR

This study uses radiation magnetohydrodynamics simulations to explore how small-scale magnetic fields influence solar granules, revealing that magnetic flux affects brightness and intensity fluctuations without altering temperature structure.

Contribution

It provides the first detailed numerical analysis of the interaction between solar granules and small-scale magnetic fields across different magnetic flux levels.

Findings

Density and gas pressure profiles change significantly with magnetic flux.

Brightness of solar granulation varies substantially with magnetic flux.

Total rms intensity fluctuations remain roughly constant despite magnetic flux variations.

Abstract

We have carried out numerical simulation based on the equations of radiation magnetohydrodynamics to study the interaction of solar granules and small-scale magnetic fields in photospheric regions with various magnetic fluxes. Four sequences of 2D time-dependent models were calculated for photospheric regions with average vertical magnetic fluxes of 0, 10, 20, and 30 mT. The models exhibit no substantial variations in their temperature structure with varying average field strength, while the density and gas pressure profiles display gross changes. The solar granulation brightness field also varies substantially with magnetic flux. The contribution of the small-scale component to the intensity power spectrum increases with average field strength, whereas the large-scale component (of about a granule size) contributes less, the total rms intensity fluctuations being approximately the same. Thus the observed decrease in rms intensity fluctuations with growing average magnetic flux can be interpreted as smoothing of the small-scale component in the power spectrum by the modulation transfer function of the telescope.