Ion VDFs for the 2025 June 15 and 2015 January 12 events. Panels (a) and (e) show the one-dimensional reduced ion phase-space density (PSD) as a function of the ﹩{V}_{L}﹩. The black solid lines indicate the calculated ion bulk velocity projected onto the ﹩L﹩ direction. The vertical dashed lines mark the representative times selected for the two-dimensional distributions. Panels (b)–(d) and (f)–(h) present the corresponding two-dimensional reduced ion VDFs in the ﹩{V}_{L}﹩–﹩{V}_{N}﹩ plane at the indicated times. The white stars denote the ﹩{{\rm{H}}}^{+}﹩ bulk velocity. The cyan arrows indicate the ﹩{{\rm{He}}}^{2+}﹩.