Exact scaling laws and the local structure of isotropic magnetohydrodynamic turbulence
arXiv:astro-ph/0611692 · doi:10.1017/S0022112006004186
Abstract
This paper examines the consistency of the exact scaling laws for isotropic MHD turbulence in numerical simulations with large magnetic Prandtl numbers Pm and with Pm=1. The exact laws are used to elucidate the structure of the magnetic and velocity fields. Despite the linear scaling of certain third-order correlation functions, the situation is not analogous to the case of Kolmogorov turbulence. The magnetic field is adequately described by a model of stripy (folded) field with direction reversals at the resistive scale. At currently available resolutions, the cascade of kinetic energy is short-circuited by the direct exchange of energy between the forcing-scale motions and the stripy magnetic fields. This nonlocal interaction is the defining feature of isotropic MHD turbulence.
10 pages, 6 figures. Accepted for publication in Journal of Fluid Mechanics
References in corpus (3)
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