Basic Properties of MHD Turbulence in the Inertial Range

TL;DR

This paper investigates the spectral slope and anisotropy in MHD turbulence, providing precise measurements that support the Goldreich-Sridhar -5/3 slope and quantify anisotropy, enhancing understanding of astrophysical turbulence.

Contribution

It offers the first precise measurements of anisotropy constant and confirms the spectral slope in MHD turbulence, refining the theoretical model of the cascade.

Findings

Spectral slope favors -5/3 over -3/2

Anisotropy constant C_A=0.34 measured

Kolmogorov constant C_K=4.2 (or 3.3 for Alfvenic case)

Abstract

We revisit the issue of spectral slope of MHD turbulence in the inertial range and argue that numerics favor Goldreich-Sridhar -5/3 slope rather than -3/2 slope. We also did precision measurements of anisotropy of MHD turbulence and determined the anisotropy constant C_A=0.34 of Alfvenic turbulence. Together with previously measured Kolmogorov constant C_K=4.2, or 3.3 for purely Alfvenic case, it constitutes a full description of MHD cascade in terms of spectral quantities, which is of high practical value for astrophysics.