Universal properties of three-dimensional magnetohydrodynamic turbulence: do Alfvén waves matter?

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Published 8 July 2005 IOP Publishing Ltd
, , Citation Abhik Basu and Jayanta K Bhattacharjee J. Stat. Mech. (2005) P07002 DOI 10.1088/1742-5468/2005/07/P07002

1742-5468/2005/07/P07002

Abstract

We analyse the effects of the propagating Alfvén waves, arising due to non-zero mean magnetic fields, on the nonequilibrium steady states of three-dimensional (3D) homogeneous magnetohydrodynamic (MHD) turbulence. In particular, the effects of Alfvén waves on the universal properties of 3DMHD turbulence are studied in a one-loop self-consistent mode-coupling approach. We calculate the kinetic- and magnetic-energy spectra. We find that even in the presence of a mean magnetic field the energy spectra are Kolmogorov-like, i.e., scale as k−5/3 in the inertial range where k is a Fourier wavevector belonging to the inertial range. We also elucidate the multiscaling of the structure functions in a log-normal model by evaluating the relevant intermittency exponents, and our results suggest that the multiscaling deviations from the simple Kolmogorov scaling of the structure functions decrease with increasing strength of the mean magnetic field. Our results compare favourably with many existing numerical and observational results.

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10.1088/1742-5468/2005/07/P07002