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Turbulent magnetic Prandtl number and magnetic diffusivity quenching from simulations

T. A. Yousef·A. Brandenburg·G. Rüdiger
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Abstract

Forced turbulence simulations are used to determine the turbulent kinematic viscosity, nu_t, from the decay rate of a large scale velocity field. Likewise, the turbulent magnetic diffusivity, eta_t, is determined from the decay of a large scale magnetic field. In the kinematic regime, when the field is weak, the turbulent magnetic Prandtl number, nu_t/eta_t, is about unity. When the field is nonhelical, eta_t is quenched when magnetic and kinetic energies become comparable. For helical fields the quenching is stronger and can be described by a dynamical quenching formula.

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T. A. Yousef, A. Brandenburg, G. Rüdiger. 2004-02-02. Turbulent magnetic Prandtl number and magnetic diffusivity quenching from simulations. https://doi.org/10.1051/0004-6361%3A20031371

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