Turbulent magnetic Prandtl number and magnetic diffusivity quenching from simulations
arXiv:astro-ph/0302425 · doi:10.1051/0004-6361:20031371
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.
7 pages, 6 figures