Differential rotation and meridional circulation in global models of solar convection

TL;DR

This paper reviews recent high-resolution simulations of solar convection, highlighting how turbulent motions, rotation, and heat flux interplay to maintain the Sun's differential rotation and meridional circulation.

Contribution

It provides new insights into the nonlinear dynamics of mean flows in solar convection zones through detailed spherical shell simulations.

Findings

Coriolis force induces Reynolds stress transporting angular momentum equatorward.

Latitudinal variations in convective heat flux influence flow patterns.

Complex interplay between turbulence, rotation, and entropy shapes solar differential rotation.

Abstract

In the outer envelope of the Sun and in other stars, differential rotation and meridional circulation are maintained via the redistribution of momentum and energy by convective motions. In order to properly capture such processes in a numerical model, the correct spherical geometry is essential. In this paper I review recent insights into the maintenance of mean flows in the solar interior obtained from high-resolution simulations of solar convection in rotating spherical shells. The Coriolis force induces a Reynolds stress which transports angular momentum equatorward and also yields latitudinal variations in the convective heat flux. Meridional circulations induced by baroclinicity and rotational shear further redistribute angular momentum and alter the mean stratification. This gives rise to a complex nonlinear interplay between turbulent convection, differential rotation, meridional circulation, and the mean specific entropy profile. I will describe how this drama plays out in our simulations as well as in solar and stellar convection zones.