Helicity Balance and Steady-State Strength of the Dynamo Generated Galactic Magnetic Field

TL;DR

This paper shows that including helicity flux in galactic dynamo models significantly increases the predicted steady-state magnetic field strength, reaching near equipartition levels, unlike models without flux.

Contribution

It introduces the impact of helicity flux on the nonlinear stage of galactic dynamo, revealing a radical change in magnetic field dynamics and equilibrium strength.

Findings

Helicity flux leads to near equipartition magnetic fields.

Without helicity flux, magnetic fields are substantially subequipartition.

Inclusion of flux alters the magnetic helicity balance significantly.

Abstract

We demonstrate that the inclusion of the helicity flux in the magnetic helicity balance in the nonlinear stage of galactic dynamo action results in a radical change in the magnetic field dynamics. The equilibrium value of the large-scale magnetic field is then approximately the equipartition level. This is in contrast to the situation without the flux of helicity, when the magnetic helicity is conserved locally, which leads to substantially subequipartition values for the equilibrium large-scale magnetic field.