Magnetic field reversals and galactic dynamos

TL;DR

This paper explores how magnetic field reversals in galaxies can be explained by mean-field dynamo models, highlighting the influence of seed field strength and distribution on reversal frequency.

Contribution

It demonstrates that frequent magnetic reversals in galactic dynamos depend on seed field strength and localization, offering insights into initial magnetic field conditions.

Findings

Reversals are common with strong, localized seed fields.

Reversal frequency decreases with weaker seed fields.

Observations of galactic reversals can inform seed magnetic field properties.

Abstract

We argue that global magnetic field reversals similar to those observed in the Milky Way occur quite frequently in mean-field galactic dynamo models that have relatively strong, random, seed magnetic fields that are localized in discrete regions. The number of reversals decreases to zero with reduction of the seed strength, efficiency of the galactic dynamo and size of the spots of the seed field. A systematic observational search for magnetic field reversals in a representative sample of spiral galaxies promises to give valuable information concerning seed magnetic fields and, in this way, to clarify the initial stages of galactic magnetic field evolution.