Magnetic helicity fluxes in alpha Omega dynamos

TL;DR

This paper investigates how internal magnetic helicity fluxes in turbulent alpha Omega dynamos can mitigate the quenching of large-scale magnetic field generation, emphasizing the importance of diffusive helicity fluxes in dynamo models.

Contribution

It introduces a one-dimensional mean-field dynamo model highlighting the role of internal magnetic helicity fluxes in reducing quenching effects.

Findings

Internal magnetic helicity fluxes help alleviate dynamo quenching.

Diffusive helicity fluxes are significant within a single hemisphere.

Model suggests fluxes can sustain large-scale magnetic fields at high Reynolds numbers.

Abstract

In turbulent dynamos the production of large-scale magnetic fields is accompanied by a separation of magnetic helicity in scale. The large- and small-scale parts increase in magnitude. The small-scale part can eventually work against the dynamo and quench it, especially at high magnetic Reynolds numbers. A one-dimensional mean-field model of a dynamo is presented where diffusive magnetic helicity fluxes within the domain are important. It turns out that this effect helps to alleviate the quenching. Here we show that internal magnetic helicity fluxes, even within one hemisphere, can be important for alleviating catastrophic quenching.