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Dynamo efficiency with shear in helical turbulence .

Leprovost, N and Kim, E (2009) Dynamo efficiency with shear in helical turbulence . Astrophysical Journal Letters, 696 (2). L125-L128. ISSN 1538-4357

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Abstract

To elucidate the influence of shear flow on the generation of magnetic fields through the modification of turbulence property, we consider the case where a large-scale magnetic field is parallel to a large-scale shear flow without direct interaction between the two in the kinematic limit where the magnetic field does not backreact on the velocity. By nonperturbatively incorporating the effect of shear in a helically forced turbulence, we show that turbulence intensity and turbulent transport coefficients (turbulent viscosity, α and β effect) are enhanced by a weak shear, while strongly suppressed for strong shear. In particular, β is shown to be much more strongly suppressed than α effect. We discuss its important implications for dynamo efficiency, i.e., on the scaling of the dynamo number with differential rotation.

Item Type: Article
Copyright, Publisher and Additional Information: © 2009 The American Astronomical Society. This is an author produced version of a paper published in 'Astrophysical Journal Letters'. Uploaded in accordance with the publisher's self-archiving policy.
Institution: The University of Sheffield
Academic Units: The University of Sheffield > Faculty of Science (Sheffield) > School of Mathematics and Statistics (Sheffield)
Depositing User: Mrs Megan Hobbs
Date Deposited: 17 Mar 2010 16:47
Last Modified: 14 Jun 2014 04:52
Published Version: http://dx.doi.org/10.1088/0004-637X/696/2/L125
Status: Published
Publisher: Institute of Physics Publishing
Refereed: Yes
Identification Number: 10.1088/0004-637X/696/2/L125
Related URLs:
URI: http://eprints.whiterose.ac.uk/id/eprint/10502

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