Statistical properties of two-dimensional magnetohydrodynamic turbulence
The statistical properties of two-dimensional magnetohydrodynamic (MHD) turbulence are studied by means of high-resolution numerical simulations. As a theoretical point of reference, the beta-model of intermittent turbulence is adapted to the MHD case. Comparison of simulation results for energy spectra with the beta-model predictions shows intermittency corrections to be small, while fourth-order correlation functions exhibit a stronger effect, consistent with the numerically observed Reynolds-number dependence of the flatness factor F proportional to R(lambda,1/2). An argument is given that this scaling, though valid for R(lambda) approximately equal to 100 is not characteristic of the asymptotic regime, R(lambda) tends to infinity, where a constant value of F is to be expected. The probability distributions of the field difference are Gaussian for large separation x or t, approaching an approximately exponential distribution as x,t tend to 0. This behaviour can be understood by a simple probabilistic argument. The probability distribution of the local energy dissipation rate epsilon is roughly consistent with a log-normal distribution at larger epsilon but shows a different behaviour at small epsilon.
Bibliographic Reference: Article: Physics of Fluids B, Vol. 2 (1990) No. 12, pp. 3024-3031
Record Number: 199110330 / Last updated on: 1994-12-02
Original language: en
Available languages: en