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

TL;DR

This paper compares high-resolution MHD turbulence simulations with solar wind data, revealing similar spectral index distributions and scaling laws, thus supporting MHD's applicability to solar wind fluctuations.

Contribution

It demonstrates that MHD simulations can replicate key spectral features observed in the solar wind, highlighting the relevance of MHD turbulence models.

Findings

Spectral indices in simulations match solar wind observations.

Magnetic field spectrum is steeper than velocity spectrum.

Residual energy scales approximately as k_perp^-2.

Abstract

The question is addressed to what extent incompressible magnetohydrodynamics (MHD) 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 are qualitatively and quantitatively similar to solar wind observations at 1 AU. Both simulations and observations show that in the inertial range the magnetic field spectrum E_b is steeper than the velocity spectrum E_v with E_b >~ E_v and that the residual energy E_R = E_b-E_v decreases nearly following a k_perp^-2 scaling.