Magnetic helicity in non-axisymmetric mean-field solar dynamo

TL;DR

This study investigates how magnetic helicity conservation influences the evolution of non-axisymmetric magnetic fields in a solar dynamo model, revealing transient behaviors and spatial correlations with solar magnetic patterns.

Contribution

It introduces a non-linear non-axisymmetric mean-field solar dynamo model that captures magnetic helicity transfer and its relation to solar magnetic features.

Findings

Magnetic helicity is exchanged across spectral space during transient phases.

Non-axisymmetric magnetic helicity distributions align with Hale polarity regions.

The dynamo transitions from axisymmetric to non-axisymmetric and back within a few years.

Abstract

The paper address the effects of magnetic helicity conservation in a non-linear nonaxisymmetric mean-field solar dynamo model. We study the evolution of the shallow non-axisymmetric magnetic field perturbation with the strength about 10G in the solar convection zone. The dynamo evolves from the pure axisymmetric stage through the short (about 2 years) transient phase when the non-axisymmetric m=1 dynamo mode is dominant to the final stage where the axisymmetry of the dynamo is almost restored. It is found that magnetic helicity is transferred forth and back over the spectral space during the transient phase. Also our simulations shows that the non-axisymmetric distributions of magnetic helicity tend to follows the regions of the Hale polarity rule.