Impact of X‐Rays (0.5Å–90Å) During GDS 2018 on the Production Rates of H ₂ O ⁺ , HDO ⁺ and Electron Density in the D Region Ionosphere of Mars: First Ionospheric Modeling Based on ACS/MIR‐NIR Observations From ExoMars/TGO

The vertical profiles of H 2 O, HDO and D/H mixing ratios are measured between two Martian Years (MY34‐MY35) at northern and southern hemispheres from MIR and NIR of ACS onboard the ExoMars‐TGO. These mixing ratios are compared in both hemispheres from Ls = 180° to 355° in MY34 and from Ls = 185° to 356° in MY35. We have used ACS MIR and NIR data of MY34 and MY35. In these observations 3 peaks of water abundance at Ls ∼ 200°, Ls ∼ 240° and Ls ∼ 300°–350° and 4 peaks at Ls ∼ 200°, Ls ∼ 240°, Ls ∼ 250°–300° and Ls ∼ 300°–350° are pronounced at about 40 km in northern and southern hemispheres respectively. The highest mixing ratios of H 2 O, HDO and D/H are measured in both hemispheres during the global dust storm GDS of 2018 (MY34) at Ls ∼ 200°. Using observed mixing ratios, the production rates of H 2 O + , HDO + and electron density in the D region ionosphere (∼30 km) are calculated simultaneously from AYS method due to X‐ray (0.5Å–90Å) impact in northern latitudes (∼51°N–59°N) and southern latitudes (55°S–65°S) during the dust storm and perihelion periods at Ls ∼ 200° and Ls ∼ 275° respectively. The photoelectron impact ionization rates of H 2 O + are also calculated at these Ls and latitudes. The photon impact ionization rates of H 2 O + and HDO + and photoelectron impact ionization rates of H 2 O + are ∼100 times larger than those estimated before and after the dust storm. The photoelectron production rate of H 2 O + is also larger than its photoionization rate by one order of magnitude.