Two-dimensional Hybrid Simulations of Kinetic Plasma Turbulence: Current and Vorticity vs Proton Temperature

TL;DR

This study uses high-resolution hybrid simulations to explore how proton temperature anisotropies relate to current sheets and vorticity in solar wind plasma, revealing correlations but not causality.

Contribution

It provides new insights into the spatial relationship between proton temperature, current sheets, and vorticity in kinetic plasma turbulence.

Findings

Regions with enhanced proton temperature often coincide with thin current sheets.

Strong correlation observed between proton temperature and out-of-plane vorticity.

No definitive causal link established between current sheets and temperature anisotropies.

Abstract

Proton temperature anisotropies between the directions parallel and perpendicular to the mean magnetic field are usually observed in the solar wind plasma. Here, we employ a high-resolution hybrid particle-in-cell simulation in order to investigate the relation between spatial properties of the proton temperature and the peaks in the current density and in the flow vorticity. Our results indicate that, although regions where the proton temperature is enhanced and temperature anisotropies are larger correspond approximately to regions where many thin current sheets form, no firm quantitative evidence supports the idea of a direct causality between the two phenomena. On the other hand, quite a clear correlation between the behavior of the proton temperature and the out-of-plane vorticity is obtained.