Helicity conservation in nonlinear mean-field solar dynamo

TL;DR

This paper investigates how magnetic helicity conservation affects the solar dynamo, demonstrating that it alleviates catastrophic quenching and allows the dynamo to operate at high magnetic Reynolds numbers, with boundary conditions influencing surface effects.

Contribution

It shows that magnetic helicity conservation mitigates quenching in the solar dynamo and explores the effects of boundary conditions on the alpha-effect distribution.

Findings

Dynamo operates up to magnetic Reynolds number of 10^6.

Helicity conservation alleviates catastrophic quenching.

Boundary conditions affect the alpha-effect near the surface.

Abstract

We explore the impact of magnetic helicity conservation on the mean-field solar dynamo using the axisymmetric dynamo model which includes the subsurface shear. Our results support the recent findings by Hubbard & Brandenburg (2012), who suggested that the catastrophic quenching in the mean-field dynamo is alleviated if conservation of the total magnetic helicity is taken into account. We show that the solar dynamo can operate in the wide rage of the magnetic Reynolds number up to $10^{6}$. We also found that the boundary conditions for the magnetic helicity influence the distribution of the $\alpha$-effect near the solar surface.