Quantifying the Agyrotropy of Proton and Electron Heating in Turbulent Plasmas

An important aspect of energy dissipation in weakly collisional plasmas is that of energy partitioning between different species (e.g., protons and electrons) and between different energy channels. Here we analyse pressure-strain interaction to quantify the fractions of isotropic compressive, gyrotropic, and nongyrotropic heating for each species. An analysis of kinetic turbulence simulations is compared and contrasted with corresponding observational results from Magnetospheric Multiscale Mission data in the magnetosheath. In assessing how protons and electrons respond to different ingredients of the pressure-strain interaction, we find that compressive heating is stronger than incompressive heating in the magnetosheath for both electrons and protons, while incompressive heating is stronger in kinetic plasma turbulence simulations. Concerning incompressive heating, the gyrotropic contribution for electrons is dominant over the nongyrotropic contribution, while for protons nongyrotropic heating is enhanced in both simulations and observations. Variations with plasma beta are also discussed, and protons tend to gain more heating with increasing beta.

Automated summary

This study analyzes the distribution of energy in weakly collisional plasmas, focusing on the partitioning between different species and energy channels. The fractions of isotropic compressive, gyrotropic, and nongyrotropic heating for each species are quantified through the analysis of pressure-strain interaction. Comparisons are made between kinetic turbulence simulations and Magnetospheric Multiscale Mission observation data. The results show that compressive heating is stronger than incompressive heating in the magnetosheath, while incompressive heating is stronger in kinetic plasma turbulence simulations. Gyrotropic heating dominates for electrons, while nongyrotropic heating is enhanced for protons in both simulations and observations. The impact of plasma beta on heating variations is also discussed, indicating that increasing beta leads to more heating for protons.