Title:	Numerical studies of dynamo action in a turbulent shear flow. I.
Authors:	Singh, Nishant K. Jingade, Naveen
Issue Date:	Jun-2015
Publisher:	IOP Sciences for The American Astronomical Society
Citation:	The Astronomical Journal, 2015, Vol 806, p118
Abstract:	We perform numerical experiments to study the shear dynamo problem where we look for the growth of a large-scale magnetic field due to non-helical stirring at small scales in a background linear shear flow in previously unexplored parameter regimes. We demonstrate the large-scale dynamo action in the limit where the fluid Reynolds number ($\operatorname{Re}$) is below unity while the magnetic Reynolds number (${\rm Rm}$) is above unity; the exponential growth rate scales linearly with shear, which is consistent with earlier numerical works. The limit of low $\operatorname{Re}$ is particularly interesting, as seeing the dynamo action in this limit would provide enough motivation for further theoretical investigations, which may focus attention on this analytically more tractable limit of $\operatorname{Re}\lt 1$ compared to the more formidable limit of $\operatorname{Re}\gt 1$. We also perform simulations in the regimes where (i) both ($\operatorname{Re}$, ${\rm Rm}$) < 1, and (ii) $\operatorname{Re}\gt 1$ and ${\rm Rm}\lt 1$, and compute all of the components of the turbulent transport coefficients (${{\alpha }_{ij}}$ and ${{\eta }_{ij}}$) using the test-field method. A reasonably good agreement is observed between our results and the results of earlier analytical works in similar parameter regimes.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/6298
ISSN:	0004-6256 1538-3881 (Online)
Alternative Location:	http://adsabs.harvard.edu/abs/2015ApJ...806..118S http://arxiv.org/abs/1309.0200 http://dx.doi.org/10.1088/0004-637X/806/1/118
Copyright:	2015 The American Astronomical Society
Appears in Collections:	Research Papers (A&A)

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