Scaling laws and diffuse locality of balanced and imbalanced magnetohydrodynamic turbulence

Abstract

The search of ways to generalize the theory of strong MHD turbulence for the case of non-zero cross-helicity (or energy imbalance) has attracted considerable interest recently. In our earlier publications, we performed three-dimensional numerical simulations and showed that some of the existing models are inconsistent with numerics. In this Letter, we focused our attention on low-imbalance limit and performed new high-resolution simulations. The results strongly suggest that in the limit of small imbalances we smoothly transition to a standard Goldreich-Sridhar balanced model. We also claim that the Perez-Boldyrev model that predicts the same nonlinear timescale for both components due to the so-called dynamic alignment strongly contradicts numerical evidence. © 2010. The American Astronomical Society. All rights reserved.