Violation of critical balance and dynamic alignment in anisotropic magnetohydrodynamic turbulence

Accurate modeling of magnetized flows, from astrophysical settings to fusion devices like ITER, is impeded by the lack of a consistent theory of magnetohydrodynamic (MHD) turbulence. A central debate persists between the Kolmogorov-like ( k-5/3 ) and Iroshnikov-Kraichnan ( k-3/2 ) scaling laws. Here, we resolve this ambiguity using high-resolution numerical simulations of anisotropic MHD turbulence with moderate and large mean magnetic fields. We demonstrate that energy spectra, multiscale energy transfers, and structure functions provide robust support for the Kolmogorov scaling. We further assess the validity of critical balance and scale-dependent dynamic scaling–two pivotal hypotheses in MHD turbulence. Our simulations reveal that the normalized velocity-magnetic field correlation remains scale-independent; this is consistent with Kolmogorov scaling but inconsistent with Boldyrev’s scale-dependent dynamic alignment hypothesis. Additionally, we demonstrate that the critical balance relation linking longitudinal and transverse length scales, proposed by Goldreich and Sridhar, is also violated for a large mean magnetic field. These insights into turbulence dynamics have direct implications for predictive modeling, ranging from laboratory fusion devices to astrophysical phenomena such as the solar corona, dynamos, accretion disks, and astrophysical jets.