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Moffatt drift driven large scale dynamo due to alpha fluctuations with nonzero correlation times (NOTE: UNUSUAL VENUE)
  Nordita Astrophysics seminars

Wednesday 29 April 2015
from 13:30 to 14:15
at 132:028 Nordita East
Speaker : Nishant Singh (Nordita)
Abstract : We present a theory of large--scale dynamo action in a turbulent flow that has stochastic, zero--mean fluctuations of the $\alpha$ parameter. Statistically inhomogeneous $\alpha$ fluctuations give rise to finite Moffatt drift which always contributes positively to the dynamo growth if correlation time of alpha fluctuations be nonzero. We find that there exists a wavenumber cutoff at some large $k$ beyond which the growth rate turns negative. This makes it a special dynamo as the magnetic power at smallest length scales would be suppressed due to the existence of wavenumber cutoff, thus enabling a bonafide large--scale dynamo.

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