Double-Cell Type Solar Meridional Circulation Based on Mean-Field Hydrodynamic Model

TL;DR

This paper demonstrates through mean-field hydrodynamic simulations that a double-cell meridional circulation in the Sun can be driven by specific Reynolds stress conditions, aligning with recent helioseismic observations.

Contribution

First to confirm that the double-cell meridional circulation can be achieved with Reynolds stress transporting angular momentum upward and downward in the convection zone.

Findings

Double-cell circulation is achieved with specific Reynolds stress conditions.

Reynolds stress transports angular momentum upward in the lower and downward in the upper convection zone.

Angular momentum is advected to both layers by the two circulation cells.

Abstract

The main object of the paper is to present the condition of the non-diffusive part of the Reynolds stress for driving the double-cell structure of the solar meridional circulation, which has been revealed by recent helioseismic observations. By conducting a set of mean-field hydrodynamic simulations, we confirm for the first time that the double-cell meridional circulation can be achieved along with the solar-like differential rotation when the Reynolds stress transports the angular momentum upward in the lower part and downward in the upper part of the convection zone. It is concluded that, in a stationary state, the accumulated angular momentum via the Reynolds stress in the middle layer is advected to both the upper and lower parts of the convection zone by each of the two meridional circulation cells, respectively.