Nonperturbative quasilinear approach to the shear dynamo problem

Sridhar, S.; Subramanian, Kandaswamy

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/3902

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DC Field	Value	Language
dc.contributor.author	Sridhar, S.	-
dc.contributor.author	Subramanian, Kandaswamy	-
dc.date.accessioned	2010-07-09T09:08:52Z	-
dc.date.available	2010-07-09T09:08:52Z	-
dc.date.issued	2009-12	-
dc.identifier.citation	Physical Review E, 2009, Vol.80, p066315	en
dc.identifier.issn	1550-2376 -E	-
dc.identifier.issn	1539-3755 -P	-
dc.identifier.uri	http://hdl.handle.net/2289/3902	-
dc.description	Open Access	en
dc.description.abstract	We study large-scale dynamo action due to turbulence in the presence of a linear shear flow. Our treatment is quasilinear and equivalent to the standard “first-order smoothing approximation.” However it is non perturbative in the shear strength. We first derive an integrodifferential equation for the evolution of the mean magnetic field, by systematic use of the shearing coordinate transformation and the Galilean invariance of the linear shear flow. We show that, for nonhelical turbulence, the time evolution of the cross-shear components of the mean field do not depend on any other components excepting themselves; this is valid for any Galilean-invariant velocity field, independent of its dynamics. Hence, to all orders in the shear parameter, there is no shear-current-type effect for non helical turbulence in a linear shear flow in quasilinear theory in the limit of zero resistivity. We then develop a systematic approximation of the integro-differential equation for the case when the mean magnetic field varies slowly compared to the turbulence correlation time. For nonhelical turbulence, the resulting partial differential equations can again be solved by making a shearing coordinate transformation in Fourier space. The resulting solutions are in the form of shearing waves, labeled by the wave number in the sheared coordinates. These shearing waves can grow at early and intermediate times but are expected to decay in the long time limit.	en
dc.language.iso	en	en
dc.publisher	American Physical Society	en
dc.relation.uri	http://adsabs.harvard.edu/abs/2009PhRvE..80f6315S	en
dc.relation.uri	http://arxiv.org/abs/0906.3073	en
dc.relation.uri	http://dx.doi.org/10.1103/PhysRevE.80.066315	en
dc.rights	2009 by the American Physical Society	en
dc.title	Nonperturbative quasilinear approach to the shear dynamo problem	en
dc.type	Article	en
Appears in Collections:	Research Papers (A&A)

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