Identifying Kinetic Plasma Wave Modes Observed in the Acceleration Regions in the Low-Latitude Boundary Layer.

Abstract:

Understanding plasma heating and transport across fluid, ion and electron scales is currently not well understood in astrophysical plasmas. We have recently identified (by determining the observational dispersion relation using multi-point spacecraft measurements) an ion-scale, large amplitude fast mode wave observed inside a fluid-scale Kelvin-Helmholtz vortex. The Poyinting flux of the fast mode wave packet was sufficient to produce the observed ~5 keV energy increase of ions of magnetosheath origin. In this followup work, we analyze in detail the other intervals with similar characteristics, where the cold magnetosheath population becomes significantly energized. We identify the plasma wave modes present and discuss whether their energy budget is sufficient for the observed level of energization.