Model results compared with the SWAP pickup ion observations from Figure 2. Vertical dashed lines indicating the peak locations of the solar wind (i.e., solar wind bulk flow speed in SWAP’s frame), He⁺⁺, and the energy cutoff of H⁺ pickup ions at twice the solar wind speed (four times the energy). The fit for H⁺ included points (green) that cover the low energy range and just below the pickup ion cutoff. The model curve for He⁺ (orange) is far simpler, and depends only on the variation in the He photoionization rate, so significant differences from the data are not unexpected.