Shell model for stratified convection: implications for the solar convective conundrum

TL;DR

This paper introduces a shell model for stratified convection to better understand the solar convective conundrum, showing that convection suppression at depth can occur without rotation or magnetic influences.

Contribution

A novel shell model for stratified, nonmagnetic, nonrotating convection at low Mach number, tailored to stellar stratification profiles, providing new insights into solar convection behavior.

Findings

Convective amplitudes decrease with depth at low Prandtl number.

Suppression of deep convection can occur without rotation or magnetic fields.

Model offers a potential explanation for the solar convective conundrum.

Abstract

We extend the notion of a shell model to stratified systems, and propose one that represents stratified, nonmagnetic, nonrotating convection at low Mach number. Motivated by profiles of background stratification that support convection in stars such as the Sun, we study numerical solutions corresponding to a highly unstable layer above a mildly unstable layer. We find that at low Prandtl number, convective amplitudes decrease with depth in the lower layer. This suggests that the suppression of convection in the deeper layers of the Sun's convection zone (the convective conundrum) can be addressed without necessarily appealing to rotation or magnetic fields.