Skip to main content
Article thumbnail
Location of Repository

Preprint typeset using L ATEX style emulateapj v. 10/09/06 NONLINEAR MAGNETIC DIFFUSIVITY AND ALPHA TENSORS IN HELICAL TURBULENCE

By A. Br, K. -h. Rädler, M. Rheinhardt and K. Subramanian

Abstract

The effect of a dynamo-generated magnetic field of Beltrami type on turbulent transport coefficients is studied. Although the turbulence becomes anisotropic and inhomogeneous, the dependence of the mean electromotive force on the mean field can still be expressed in terms of a pseudoscalarα and a scalar turbulent magnetic diffusivityηt. Using the testfield method the dependence ofαandηt on the magnetic Reynolds number ReM is determined for magnetic fields that are in equipartition with the velocity field. Increasing ReM from 2 to 600 reducesηt only by a factor of 2, suggesting that the quenching ofηt is, in contrast to the 2-dimensional case, essentially independent of ReM. Over the same range of ReM,αis reduced by a factor of 8, but this can be explained by a corresponding increase of a magnetic contribution to theαeffect with opposite sign. Within this framework, the corresponding kinetic contribution to theαeffect turns out to be independent of ReM for 2≤ReM ≤ 600. The level of fluctuations ofαandηt is only 10 % and 20 % of the respective kinematic reference values. Subject headings: MHD – turbulence 1

OAI identifier: oai:CiteSeerX.psu:10.1.1.313.41
Provided by: CiteSeerX
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://citeseerx.ist.psu.edu/v... (external link)
  • http://arxiv.org/pdf/0805.1287... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.