Particle flux ratios during the Rosetta mission 2014–2016. (A) Helium species. The 1 h averaged He⁺ /He²⁺ ratio measured by RPC-ICA (black) is compared to the daily averaged analytical forward model solution (blue), with mean speed U_sw = U_ICA(He²⁺). The column density is derived from ROSINA data. Modeled He⁰/He²⁺ flux ratios are shown in red. (B) Hydrogen species, with modeled H⁰/H⁺ (blue) and H⁻/H⁺ (red) ratios for a solar wind mean speed of U_sw = U_ICA(H⁺). The solar wind ion cavity is designated as a gradually denser gray-shaded region. Safe mode and excursions where ROSINA data were excluded from the analysis are indicated.