THE TURBULENT MAGNETIC PRANDTL NUMBER OF MHD TURBULENCE IN DISKS
نویسندگان
چکیده
منابع مشابه
The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks
The magnetic Prandtl number PrM is the ratio of viscosity to resistivity. In astrophysical disks the diffusion of angular momentum (viscosity) and magnetic fields (resistivity) are controlled by turbulence. Phenomenological models of the evolution of large scale poloidal magnetic fields in disks suggest that the turbulent magnetic Prandtl number PrM,T controls the rate of escape of vertical fie...
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In turbulent MHD systems where the ratio of fluid viscosity and magnetic diffusivity (the magnetic Prandtl number, Pr = ν/η) is very large, there exists a broad range of subviscous scales available to magnetic fluctuations, but not to hydrodynamic ones. This MHD regime is encountered, for example, in such astrophysical environments as the interstellar medium and protogalactic plasmas, where Pr ...
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In this paper, we derive a general relationship for the turbulent Prandtl number Pr t for homogeneous stably stratified turbulence from the turbulent kinetic energy and scalar variance equations. A formulation for the turbulent Prandtl number, Pr t , is developed in terms of a mixing length scale LM and an overturning length scale LE , the ratio of the mechanical (turbulent kinetic energy) deca...
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We investigate the behavior of the magnetic Prandtl number (ratio of microscopic viscosity to resistivity) for accretion sources. Generally this number is very small in standard accretion disk models, but can become larger than unity within ∼ 50 Schwarzschild radii of the central mass. Recent numerical investigations suggest a marked dependence of the level of MHD turbulence on the value of the...
متن کاملTurbulent magnetic Prandtl number and magnetic diffusivity quenching from simulations
Forced turbulence simulations are used to determine the turbulent kinematic viscosity, νt, from the decay rate of a large scale velocity field. Likewise, the turbulent magnetic diffusivity, ηt, 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, νt/ηt, is about unity. When the field is nonhelical, ...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2009
ISSN: 0004-637X,1538-4357
DOI: 10.1088/0004-637x/697/2/1901