Turbulent magnetic Prandtl number and magnetic diffusivity quenching from simulations

2003/02/28 by T. A. Yousef, A. Brandenburg, G. Rüdiger
Physics and Astronomy · #astro-ph

paper · pdf · doi:10.1051/0004-6361:20031371

published as Astron.Astrophys. 411 (2003) 321-328 · 7 pages, 6 figures

arxiv created 2004/02/02 · arxiv updated 2009/12/01

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.

Related

• α Effect and Magnetic Diffusivity β in Helical Plasma under Turbulence Growth
• Turbulent magnetic Prandtl numbers obtained with MHD Taylor-Couette flow experiments
• The Nonlinear Turbulent Dynamo
• Recent Developments in Magnetic Dynamo Theory
• Small-scale turbulent dynamo for low-Prandtl number fluid: comparison of the theory with results of numerical simulations