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Paper: |
Understanding Nonlinear Cascades in Magnetohydrodynamic Turbulence by Statistical Closure Theory |
Volume: |
429, Numerical Modeling of Space Plasma Flows, Astronum-2009 |
Page: |
28 |
Authors: |
Müller, W.; Malapaka, S. K. |
Abstract: |
It is shown that supposedly universal scaling relations between second-order statistical moments
of magnetohydrodynamic turbulence can be found with the help of the eddy-damped quasi-normal statistical
closure theory (EDQNM). As an example, the inertial
range scaling behaviour of the spectrum of magnetic helicity in direct numerical simulations
of three-dimensional magnetohydrodynamic turbulence driven at small scales is theoretically
studied. Using a hypothesis of dynamical equilibrium the inertial range spectrum is found to
depend on various quantities: kinetic and magnetic energy as well as kinetic helicity.
The influence of kinetic helicity explains numerical results that are in apparent
contradiction to previous theoretical and numerical work. A similar approach towards the residual energy spectrum in
magnetohydrodynamic turbulence is also touched upon. |
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