  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 which 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.
