The effect of rotation on the dynamo threshold at the low Pm limit

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• Vassilios Dallas (Leeds)
• Monday 22 May 2017, 16:00-17:00
• MR14, Centre for Mathematical Sciences, Wilberforce Road, Cambridge.

If you have a question about this talk, please contact Robert Teed.

In this seminar I will show that the critical magnetic Reynolds number Rm_c for a turbulent non-helical dynamo in the low magnetic Prandtl number Pm limit can be significantly reduced if the flow is submitted to global rotation. Even for moderate rotation rates the required energy injection rate can be reduced by a factor more than 10^3. This strong decrease of the onset is attributed to the reduction of the turbulent fluctuations that makes the flow to have a much larger cut-off length-scale compared to a non-rotating flow of the same Reynolds number. The dynamo thus behaves as if it is driven by laminar behaviour (i.e. high Pm behaviour) even at high values of the Reynolds number (i.e. at low values of Pm). Our finding thus points into a new paradigm for the design of new liquid metal dynamo experiments.

This talk is part of the DAMTP Astrophysics Seminars series.

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• MR14, Centre for Mathematical Sciences, Wilberforce Road, Cambridge
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