Spectral scaling laws in magnetohydrodynamic turbulence simulations and in the solar wind

Abstract

The question is addressed as to what extent incompressible magnetohydrodynamics can describe random magnetic and velocity fluctuations measured in the solar wind. It is demonstrated that distributions of spectral indices for the velocity, magnetic field, and total energy obtained from high-resolution numerical simulations of magnetohydrodynamic turbulence are qualitatively and quantitatively similar to solar wind observations at 1AU. Both simulations and observations show that in the inertial range the magnetic field spectrum Eb is steeper than the velocity spectrum Ev with Eb ≳ Ev and that the magnitude of the residual energy ER = Ev - Eb decreases nearly following a k -2 scaling. © 2011. The American Astronomical Society. All rights reserved.