Effects of fluctuation on alpha-omega dynamo models

TL;DR

This paper investigates how fluctuations in the alpha-effect influence alpha-omega dynamo models, revealing a new mechanism for magnetic field generation driven by mean shear and fluctuations, independent of a mean alpha-effect.

Contribution

It demonstrates that fluctuations can enable dynamo action without a mean alpha-effect and significantly alter the timescale of dynamo waves.

Findings

Fluctuations can drive magnetic field generation in alpha-omega dynamos.

Dynamo waves' timescales are strongly affected by fluctuations.

A new fluctuation-driven dynamo mechanism is identified.

Abstract

We analyse the role of a fluctuating alpha-effect in alpha-omega dynamo models, and show that there is a mechanism for magnetic field generation, valid at large scale separation, deriving from the interaction of mean shear and a fluctuating alpha-effect. It is shown that this effect can act as a dynamo even in the absence of a mean alpha-effect, and that the timescale for dynamo waves is strongly affected by the presence of fluctuations.