Authors: Rui Huang (University of Iowa), Gregory Howes (University of Iowa)

We diagnose the characteristics of ion cyclotron damping (iCD), focusing on energy transfer between the electromagnetic (EM) fields and plasma particles. Using EM fields constructed from a single ion cyclotron wave (ICW) eigenmode of the linearized Vlasov-Maxwell system, we compute field-particle correlations from Liouville mapping data. These correlations are plotted in velocity space and capture the long-term behavior of the velocity-space distribution of particle energization.

Our results show that: (i) iCD produces a quadrupolar pattern in the $(v_x, v_y)$ plane, which depends on the phase difference between the ion bulk flow and the electric field; (ii) iCD leads to net energization along $v_\perp$ near the $n = 1$ resonant velocity in the $(v_\parallel, v_\perp)$ plane, driven by pitch-angle scattering and the outward drift (both in the ICW frame); (iii) these features remain largely unchanged across variations in ion plasma beta $\beta_i$.

These findings will serve as a reference for future detection of iCD signatures in spacecraft observations.