Magnetic helicity in non-axisymmetric mean-field dynamo

V. V. Pipin

Institute of Solar-Terrestrial Physics, Russian Academy of Sciences, Irkutsk, Russia

Abstract
The paper addresses the effects of magnetic helicity conservation in a non-linear non-axisymmetric mean-field solar dynamo model. The evolution of a shallow non-axisymmetric magnetic field perturbation with a strength of about 10 G in the solar convection zone is studied. Dynamo evolves from the pure axisymmetric stage through a short (about 2 years) transient phase when the non-axisymmetric m= 1 dynamo mode is dominant at the final stage, where the axisymmetry of 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 show that the non-axisymmetric distributions of magnetic helicity follow to the regions of the Hale's polarity rule. Figs 4, Refs 17.