Turbulent transport coefficients and residual energy in mean-field dynamo theory

Journal Article · Fri Feb 15 04:00:00 EST 2008 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2839767· OSTI ID:21103808

Hamba, Fujihiro ^[1]; Sato, Hisanori ^[2]

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1. Institute of Industrial Science, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8505 (Japan)
2. Japan Patent Office, Kasumigaseki, Chiyoda-ku, Tokyo 100-8915 (Japan)

The turbulent electromotive force in the mean-field equation needs to be modeled to predict a large-scale magnetic field in magnetohydrodynamic turbulence at high Reynolds number. Using a statistical theory for inhomogeneous turbulence, model expressions for transport coefficients appearing in the turbulent electromotive force are derived including the {alpha} coefficient and the turbulent diffusivity. In particular, as one of the dynamo effects, the pumping effect is investigated and a model expression for the pumping term is obtained. It is shown that the pumping velocity is closely related to the gradient of the turbulent residual energy, or the difference between the turbulent kinetic and magnetic energies. The production terms in the transport equation for the turbulent electromotive force are also examined and the validity of the model expression is assessed by comparing with earlier results concerning the isotropic {alpha} coefficient. The mean magnetic field in a rotating spherical shell is calculated using a turbulence model to demonstrate the pumping effect.

• OSTI ID: 21103808
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 2 Vol. 15; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ELECTROMOTIVE FORCE
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MEAN-FIELD THEORY
PLASMA
POISSON EQUATION
PUMPING
REYNOLDS NUMBER
SPHERICAL CONFIGURATION
STATISTICAL MODELS
TRANSPORT THEORY
TURBULENCE