Kinetic Signatures and Intermittent Turbulence in the Solar Wind Plasma

TL;DR

This study reveals how kinetic effects and intermittent turbulence in the solar wind are linked to coherent structures like current sheets, which are associated with plasma heating and instabilities, providing new insights into plasma dynamics.

Contribution

It demonstrates the spatial correlation between kinetic effects, turbulence, and coherent structures in the solar wind, highlighting the role of instabilities in plasma heating.

Findings

Kinetic effects are concentrated near current sheets.

Coherent structures are linked to plasma instabilities.

Protons are significantly hotter near these structures.

Abstract

A connection between kinetic processes and intermittent turbulence is observed in the solar wind plasma using measurements from the Wind spacecraft at 1 AU. In particular, kinetic effects such as temperature anisotropy and plasma heating are concentrated near coherent structures, such as current sheets, which are non-uniformly distributed in space. Furthermore, these coherent structures are preferentially found in plasma unstable to the mirror and firehose instabilities. The inhomogeneous heating in these regions, which is present in both the magnetic field parallel and perpendicular temperature components, results in protons at least 3-4 times hotter than under typical stable plasma conditions. These results offer a new understanding of kinetic processes in a turbulent regime, where linear Vlasov theory is not sufficient to explain the inhomogeneous plasma dynamics operating near non-Gaussian structures.