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MHD Turbulence at Moderate Magnetic Reynolds NumberIn the present article we will consider the decay of MHD turbulence under the influence of a strong external magnetic field at moderate magnetic Reynolds numbers. Typical values of R(sub m) that are considered here range from R(sub m) approx. 0.1 to R(sub m) approx. 20. As a comparison, the initial kinetic Reynolds number common to all our simulations is Re(sub L) = 199. This means that the range of Prandtl numbers explored is 5 x 10(exp -4) to 10(exp -1). Our motivation is mainly to exhibit how the transition from the QS approximation to FMHD occurs. At the lowest values of R(sub m) studied here, the QS approximation is shown to model the flow faithfully. However, for the higher values of R(sub m) considered, it is clearly inadequate but can be replaced by another approximation which will be referred to as the Quasi-Linear (QL) approximation. Another objective of the present study is to describe how variations in the magnetic Reynolds number (while maintaining all other parameters constant) affect the dynamics of the flow. This complements past studies where variations in either the strength of the external magnetic field or the kinetic Reynolds number were considered. This article is organized as follows. In section 2 we recall the definition of the quasi-static approximation. Section 3 is devoted to the description of the numerical experiments performed using the quasi-static approximation and full MHD. In section 4 we describe the quasi-linear approximation and test it numerically against full MHD. A concluding summary is given in section 5.
Document ID
20040031710
Acquisition Source
Headquarters
Document Type
Other
Authors
Knaepen, B. (Stanford Univ. Stanford, CA, United States)
Kassinos, S. (Cyprus Univ. Nicosia, Cyprus)
Carati, D. (Free Univ. Brussels, Belgium)
Date Acquired
September 7, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Center for Turbulence Research Annual Research Briefs 2003
Subject Category
Fluid Mechanics And Thermodynamics
Funding Number(s)
CONTRACT_GRANT: ARC-02/07-283
CONTRACT_GRANT: NCC2-1371
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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