Solar wind magnetic turbulence: Inferences from spectral shape

TL;DR

This paper interprets differences in spectral slopes of solar wind turbulence through thermodynamics, confirming Kolmogorov slopes and estimating turbulent collision frequencies and energy input rates.

Contribution

It provides a thermodynamical interpretation of spectral slope differences and estimates key turbulence parameters like collision frequency and energy input in solar wind.

Findings

Confirmed Kolmogorov spectral slopes in solar wind turbulence

Estimated turbulent collision frequencies below 200 Hz

Determined energy input rate of about 50 eV/s in the inertial range

Abstract

Some differences between theoretical, numerical and observational determinations of spectral slopes of solar wind turbulence are interpreted in the thermodynamical sense. Confirmations of turbulent Kolmogorov slopes in solar wind magnetic turbulence and magnetohydrodynamic simulations exhibit tiny differences. These are used to infer about entropy generation in the turbulent cascade and to infer about the anomalous turbulent collision frequency in the dissipative range as well as the average energy input in solar wind turbulence. Anomalous turbulent collision frequencies are obtained of the order of v < 200 Hz. The corresponding stationary solar wind magnetic energy input into magnetic turbulence in the Kolmogorov inertial range is obtained to be of the order of 50 eV/s. Its thermal fate is discussed.