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Influence of turbulence on the dynamo threshold

Jean-Philippe Laval·Pierre Blaineau·Nicolas Leprovost·Bérengère Dubrulle·François Daviaud
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Abstract

We use direct and stochastic numerical simulations of the magnetohydrodynamic equations to explore the influence of turbulence on the dynamo threshold. In the spirit of the Kraichnan-Kazantsev model, we model the turbulence by a noise, with given amplitude, injection scale and correlation time. The addition of a stochastic noise to the mean velocity significantly alters the dynamo threshold. When the noise is at small (resp. large) scale, the dynamo threshold is decreased (resp. increased). For a large scale noise, a finite correlation time reinforces this effect.

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Jean-Philippe Laval, Pierre Blaineau, Nicolas Leprovost, Bérengère Dubrulle, François Daviaud. 2006-01-10. Influence of turbulence on the dynamo threshold. https://doi.org/10.1103/physrevlett.96.204503

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