Non-Gaussian probability distribution functions in two-dimensional magnetohydrodynamic turbulence

摘要

Intermittency in MHD turbulence has been analyzed using high-resolution 2D numerical simulations. We show that the Probability Distribution Functions (PDFs) of the fluctuations of the Elsasser fields, magnetic field and velocity field depend on the scale at hand, that is they are self-affine. The departure of the PDFs from a Gaussian function can be described through the scaling behavior of a single parameter lambda(r)(2) obtained by fitting the PDFs with a given curve stemming from the analysis of a multiplicative model by Castaing et al. (Physica D, 46 (1990) 177). The scaling behavior of the parameter lambda(r)(2) can be used to extract information about the intermittency. A comparison of intermittency properties in different MHD turbulent flows is also performed. [References: 21]