Angular momentum transport by magnetoconvection and the magnetic modulation of the solar differential rotation
Abstract
In order to explain the variance of the solar rotation law during the activity minima and maxima, the angular momentum transport by rotating magnetoconvection is simulated in a convective box penetrated by an inclined azimuthal magnetic field. Turbulenceinduced kinetic and magnetic stresses and the Lorentz force of the largescale magnetic background field are the basic transporters of angular momentum. Without rotation, the sign of the magnetic stresses naturally depends on the signs of the field components as positive (negative) B_{θ}B_{ϕ} transport the angular momentum poleward (equatorward). For fast enough rotation, however, the turbulenceoriginated Reynolds stresses start to dominate the transport of the angular momentum flux. The simulations show that positive ratios of the two meridional magnetic field components to the azimuthal field reduce the inward radial as well as the equatorward latitudinal transport, which result from hydrodynamic calculations. Only for B_{θ}B_{ϕ} > 0 (generated by solartype rotation laws with an accelerated equator) does the magneticinfluenced rotation at the solar surface prove to be flatter than the nonmagnetic profile together with the observed slight spindown of the equator. The latter phenomenon does not appear for antisolar rotation with polar vortex as well as for rotation laws with prevailing radial shear.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 May 2021
 DOI:
 10.1051/00046361/202039912
 arXiv:
 arXiv:2010.13601
 Bibcode:
 2021A&A...649A.173R
 Keywords:

 magnetic fields;
 Sun: rotation;
 convection;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 10 pages