Comparison between modeled ion and electron density profiles from the nominal simulation (solid lines) and mean MAVEN NGIMS measurements (open circles) during the DD2 period. (a) Results for O﹩{}_{2}^{+}﹩, O⁺, CO﹩{}_{2}^{+}﹩, NO⁺, HCO⁺, N﹩{}_{2}^{+}﹩, CO⁺, and electrons. (b) Results for OH⁺, H₂O⁺, H₃O⁺, Ar⁺, and C⁺. Electron densities are derived by assuming charge neutrality. The modeled sum of CO⁺ and N﹩{}_{2}^{+}﹩ densities is displayed for comparison with the mean NGIMS measurements at the M/Z = 28 channel, where M/Z denotes the mass-to-charge ratio.