Comparison of the diffusion coefficient as used in this work (median model) to the approximated BPL wave spectrum (see Figure 8) on which the pitch-angle-dependent resonance from M. A. Malkov et al. (2024) was applied. To assess the smoothness of both curves, they were fitted with smooth BPLs following Equation (A2) (dashed lines). The two lower panels show the relative differences of these fits to their corresponding models (middle panel: median model; bottom panel: BPL model) to measure the goodness of both fits.