Kinematic turbulent dynamo in the large Prandtl number regime
نویسندگان
چکیده
منابع مشابه
Large Kinematic Dynamo and Intermittence in a Turbulent Flow
The large time asymptotics of a magnetic eld in a turbulent -correlated (in time) ow of an ideal incompressible uid are studied. It is shown that the magnetic eld exhibits the dynamo e ect (exponential stretching) unless the Lagrangian ow generated by the velocity eld is (almost surely) distance preserving; and it is intermittent unless the Lagrangian ow associated to the turbulent component of...
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This paper is a detailed report on a programme of direct numerical simulations of incompressible nonhelical randomly forced MHD turbulence that are used to settle a long-standing issue in the turbulent dynamo theory and demonstrate that the fluctuation dynamo exists in the limit of large magnetic Reynolds number Rm ≫ 1 and small magnetic Prandtl number Pm ≪ 1. The dependence of the critical Rmc...
متن کاملLarge Kinematic Dynamo and Intermittence
The large time asymptotics of a magnetic eld in a turbulent-correlated (in time) ow of an ideal incompressible uid are studied. It is shown that the magnetic eld exhibits the dynamo eeect (exponential stretching) unless the Lagrangian ow generated by the velocity eld is (almost surely) distance preserving; and it is intermittent unless the Lagrangian ow associated to the turbulent component of ...
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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 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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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2004
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20031665