Phase-space Energization of Ions in Oblique Shocks

Examining energization of kinetic plasmas in phase space is a growing topic of interest, owing to the wealth of data in phase space compared to traditional bulk energization diagnostics. Via the field-particle correlation (FPC) technique and using multiple means of numerically integrating the plasma kinetic equation, we have studied the energization of ions in phase space within oblique collisionless shocks. The perspective afforded to us with this analysis in phase space allows us to characterize distinct populations of energized ions. In particular, we focus on ions that reflect multiple times off the shock front through shock-drift acceleration, and how to distinguish these different reflected populations in phase space using the FPC technique. We further extend our analysis to simulations of three-dimensional shocks undergoing more complicated dynamics, such as shock ripple, to demonstrate the ability to recover the phase-space signatures of this energization process in a more general system. This work thus extends previous applications of the FPC technique to more realistic collisionless shock environments, providing stronger evidence of the technique's utility for simulation, laboratory, and spacecraft analysis.

Automated summary

Examining the energization of kinetic plasmas in phase space has become an increasingly important topic. By applying the field-particle correlation (FPC) technique and numerical integration of the plasma kinetic equation, we have studied the energization of ions in oblique collisionless shocks. Our analysis in phase space allows for the characterization of distinct populations of energized ions, including those reflecting multiple times off the shock front through shock-drift acceleration. We further demonstrate the applicability of the FPC technique in more realistic collisionless shock environments.