Spectra of strong MHD Turbulence from high-resolution simulations (1401.4177v1)

Abstract: Magnetohydrodynamic turbulence is a ubiquitous phenomenon in solar physics, plasma physics and astrophysics and governs many properties of the flows of well-conductive fluids. Recently, conflicting spectral slopes for the inertial range of MHD turbulence has been reported by different groups. Varying spectral shapes from earlier simulations hinted at a wider spectral locality of MHD, which necessitated higher resolution simulations and careful and rigorous numerical analysis. In this Letter we present two groups of simulations with resolution up to 4096^3 that are numerically well-resolved and has been analyzed with exact and well-tested method of scaling study. Our results from both simulation groups indicate that the power spectral slope for all energy-related quantities, such as total energy and residual energy are around -1.7, close to Kolmogorov's -5/3. This suggests that residual energy is the constant fraction, 0.15+-0.03 of the total energy and that in asymptotic regime magnetic and kinetic spectra have the same scaling. The -1.5 slope for energy and -2 slope for residual energy suggested by other groups seems to be completely inconsistent with numerics.