Eddy viscosity and laminarization of sheared flow in three dimensional reduced magnetohydrodynamic turbulence

Citation
Ej. Kim et al., Eddy viscosity and laminarization of sheared flow in three dimensional reduced magnetohydrodynamic turbulence, PHYS PLASMA, 8(8), 2001, pp. 3576-3582
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
PHYSICS OF PLASMAS
ISSN journal
1070-664X → ACNP
Volume
8
Issue
8
Year of publication
2001
Pages
3576 - 3582
Database
ISI
SICI code
1070-664X(200108)8:8<3576:EVALOS>2.0.ZU;2-M
Abstract
The effect of Alfven waves on turbulent momentum transport is studied in th ree-dimensional reduced magnetohydrodynamic turbulence. A strong external u niform magnetic field B-0 is assumed to be present orthogonal to both backg round shear flow and its inhomogeneity. Energy is injected into the fluid a nd/or magnetic field on small scales. It is shown analytically that eddy vi scosity is reduced as 1/B-0(2) for a strong B-0, due to the cancellation of the Reynolds stress by Maxwell stress. The sign of eddy viscosity is found to depend on the detailed properties of forcings. Specifically, it is posi tive for fluid forcing but depends on the anisotropy of the forcing in the case of magnetic forcing. Furthermore, it is indicated that a magnetic fiel d tends to laminarize a mean shear flow. The possible implication of these results for the dynamics of the zonal flows in tokamaks is discussed in vie w of the cancellation of stresses. (C) 2001 American Institute of Physics.