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arXiv · 0704.2217

Analysis of the Effect of a Mean Velocity Field on Mean Field Dynamo

Alejandra Kandus
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Abstract

We study semi-analytically and in a consistent manner, the generation of a mean velocity field $\bar{\mathbf{U}}$ by helical MHD turbulence, and the effect that this field can have on a Mean Field Dynamo. Assuming a prescribed, maximally helical small scale velocity field, we show that large scale flows can be generated in MHD turbulent flows, via small scale Lorentz force. These flows back-react on the mean electromotive force of a Mean Field Dynamo through new terms, leaving the original $α$ and $β$ terms explicitly unmodified. Cross-helicity plays the key role in interconnecting all the effects. In the minimal $τ$ closure that we chose to work with, the effects are stronger for large relaxation times.

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Alejandra Kandus. 2007-04-17. Analysis of the Effect of a Mean Velocity Field on Mean Field Dynamo. https://doi.org/10.1111/j.1365-2966.2007.11863.x

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