The influence of shear flow on the α- and γ-effects in helical MHD turbulence

Nicolas Leprovost, Eun Jin Kim

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We investigate the α-effect and the turbulent transport of magnetic flux (γ-effect) by considering a turbulence driven by an isotropic helical forcing in the presence of a background large-scale shear flow. Due to shear flow, the turbulence is highly anisotropic. The effect of this shear-induced anisotropy on the structure of the electromotive force is computed selfconsistently. We show that for weak shear, magnetic pumping (γ-effect) appears, and theα-effect becomes highly anisotropic: the component of the α-effect in the direction of the shear is smaller than the one in the direction perpendicular to the shear with non-vanishing nondiagonal components. However, a sufficiently strong shear leads to severe quenching of the γ- and α-effects due to shear stabilisation.

Original languageEnglish
Pages (from-to)167-182
Number of pages16
JournalGeophysical and Astrophysical Fluid Dynamics
Volume104
Issue number2-3
DOIs
Publication statusPublished - 30 Mar 2010
Externally publishedYes

Keywords

  • Dynamo
  • Shear flow

ASJC Scopus subject areas

  • Computational Mechanics
  • Astronomy and Astrophysics
  • Geophysics
  • Mechanics of Materials
  • Geochemistry and Petrology

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