Stellar dynamos with $\vec{\Omega}\times \vec{J}$ effect

TL;DR

This paper investigates axisymmetric mean-field dynamo models incorporating the $oldsymbol{ abla} imes oldsymbol{ abla} imes$ effects, including the $oldsymbol{ abla} imes oldsymbol{J}$ effect, anisotropic diffusion, and a third-order rotation effect, applied to solar and fully convective star models.

Contribution

It introduces a comprehensive dynamo model with additional turbulent induction effects, including a third-order rotation term, and explores its application to solar and fully convective star scenarios.

Findings

The $oldsymbol{ abla} imes oldsymbol{J}$ effect influences solar dynamo behavior.

A $oldsymbol{ abla} imes oldsymbol{J}$-based dynamo can operate without differential rotation.

The model suggests possible dynamo mechanisms in fully convective stars.

Abstract

We study axisymmetric mean-field dynamo models containing differential rotation, the $\alpha$ effect and the additional turbulent induction effects. The additional effects result from the combined action of rotation and an inhomogeneity of the large-scale magnetic field. The best known of them is the $\vec{\Omega}\times\vec{J}$ effect. We also include anisotropic diffusion and a new dynamo term which is of third order in the rotation vector $\vec{\Omega}$ The model calculations are carried out using the rotation profile of the Sun as obtained from helioseismic measurements and radial profiles of other quantities according to a standard model of the solar interior. In addition, we consider a dynamo model for a full sphere which is solely based on the joint induction effects of rotation and an inhomogeneity of the large-scale magnetic field, without differential rotation and the $\alpha$ effect (a $\delta^{2}$ dynamo model). This kind of dynamo model may be relevant for fully convective stars.