Intermittent Dissipation and Local Heating in the Solar Wind

TL;DR

This study provides evidence that inhomogeneous, intermittent heating near current sheets generated by MHD turbulence significantly contributes to the overall heating of the solar wind, with coherent structures playing a key role.

Contribution

It demonstrates that a small fraction of current sheets accounts for half of the plasma energy, highlighting the importance of turbulence-driven structures in solar wind heating.

Findings

Current sheets constitute 19% of data but contribute 50% of plasma energy.

Proton temperature elevations are associated with current sheets.

Number density of non-Gaussian structures correlates with proton temperature and solar wind speed.

Abstract

Evidence for inhomogeneous heating in the interplanetary plasma near current sheets dynamically generated by magnetohydrodynamic (MHD) turbulence is obtained using measurements from the ACE spacecraft. These coherent structures only constitute 19% of the data, but contribute 50% of the total plasma internal energy. Intermittent heating manifests as elevations in proton temperature near current sheets, resulting in regional heating and temperature enhancements extending over several hours. The number density of non-Gaussian structures is found to be proportional to the mean proton temperature and solar wind speed. These results suggest magnetofluid turbulence drives intermittent dissipation through a hierarchy of coherent structures, which collectively could be a significant source of coronal and solar wind heating.