Scaling Laws and Diffuse Locality of Balanced and Imbalanced Magnetohydrodynamic Turbulence

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.