INTERMITTENT HEATING IN SOLAR WIND AND KINETIC SIMULATIONS

TLDR

Low‑density astrophysical plasmas are well described by magnetohydrodynamics at large scales, but require kinetic models at ion scales to capture dissipative processes that terminate the cascade. The study compares kinetic plasma simulations with high‑resolution spacecraft observations to interpret signatures of various dissipation mechanisms. The analysis shows kinetic‑scale coherent structures, proton heating linked to these structures, and confirms the link between intermittent turbulence, coherent structures, and plasma dissipation.

Abstract

Low-density astrophysical plasmas may be described by magnetohydrodynamics at large scales, but require kinetic description at ion scales in order to include dissipative processes that terminate the cascade. Here kinetic plasma simulations and high-resolution spacecraft observations are compared to facilitate the interpretation of signatures of various dissipation mechanisms. Kurtosis of increments indicates that kinetic scale coherent structures are present, with some suggestion of incoherent activity near ion scales. Conditioned proton temperature distributions suggest heating associated with coherent structures. The results reinforce the association of intermittent turbulence, coherent structures, and plasma dissipation.