Radiative Cooling in MHD Models of the Quiet Sun Convection Zone and Corona

TL;DR

This paper presents numerical simulations of the quiet Sun's plasma and magnetic fields, exploring radiative cooling effects and energy fluxes from the convection zone to the corona, revealing the role of convective motions in energy transfer.

Contribution

It introduces an efficient approximation for radiative transport physics and investigates magnetic and energy flux dynamics in the Sun's atmosphere using MHD simulations.

Findings

Net Poynting flux is directed inward below the surface.

Electromagnetic energy flows outward into the corona.

Convective motions driven by radiative cooling generate energy fluxes.

Abstract

We present a series of numerical simulations of the quiet Sun plasma threaded by magnetic fields that extend from the upper convection zone into the low corona. We discuss an efficient, simplified approximation to the physics of optically thick radiative transport through the surface layers, and investigate the effects of convective turbulence on the magnetic structure of the Sun's atmosphere in an initially unipolar (open field) region. We find that the net Poynting flux below the surface is on average directed toward the interior, while in the photosphere and chromosphere the net flow of electromagnetic energy is outward into the solar corona. Overturning convective motions between these layers driven by rapid radiative cooling appears to be the source of energy for the oppositely directed fluxes of electromagnetic energy.