Impact of MHD Turbulence on Thermal Wind Balance in the Sun

TL;DR

This study investigates how magneto-rotational instability-driven MHD turbulence influences the thermal wind balance in the Sun, highlighting its role in solar rotation and internal structure, especially around the tachocline.

Contribution

It identifies the MRI-active regions in the Sun and links MRI-driven turbulence to thermal wind balance and internal heating, providing new insights into solar dynamics.

Findings

MRI-active regions are confined to the tachocline and near-surface shear layer.

MRI-driven turbulence contributes to maintaining thermal wind balance.

Turbulent heating from MRI may explain the warm pole around the tachocline.

Abstract

The possible role of magneto-rotational instability (MRI) and its driven MHD turbulence in the solar interior is studied on the basis of the linear and nonlinear theories coupling with physical parameters, providing solar rotation profile inverted from the helioseismic observation and a standard model for the internal structure of the sun. We find that the MRI venue is confined to the higher-latitude tachocline and lower-latitude near-surface shear layer. It is especially interesting that the MRI-active region around the tachocline closely overlaps with the area indicating a steep entropy rise which is required from the thermal wind balance in the sun. This suggests that the MRI-driven turbulence plays a crucial role in maintaining the thermal wind balance in the sun via the exceptional turbulent heating and equatorward angular momentum transports. The warm pole existing around the tachocline might be a natural outcome of the turbulent activities energized by the MRI.