Statistical isotropy in three-dimensional magnetohydrodynamic turbulence

Direct numerical simulation (DNS) of decaying isotropic three-dimensional (3D) magnetohydrodynamic (MHD) turbulence based on the 10243-modes in a periodic box is used for studying the statistical properties of turbulence. In this paper, the presence of intermittency in MHD turbulence is investigated through the analysis of the probability distribution function (PDF) for Elsaesser fields and total energy fluctuations. We observe that the PDFs of the Elsaesser fields fluctuations display strong non-Gaussian behavior at small scale, which can be ascribed to multifractality feature, while the PDFs of the total energy fluctuations have the same shape over all observed scales and are monofractal. The PDFs have stretched exponential tail and satisfy the function P(|δX|)∼exp (-A|δX|μ). Numerically, we extract the exponent μ and find that it is constant for monofractal behavior as the length scale varies. To check the notion of self-similarity in the respective fluctuations, we apply the compensated structure functions which could be a reliable way in turbulence.