The nighttime limb intensity of diffuse auroral emission of CO 2 + (B 2 Σ u + -X 2 π g ) Ultraviolet Doublet (UVD) is observed in the northern hemisphere of Mars during 17-21 December 2014 from Imaging Ultraviolet Spectrograph instrument onboard Mars Atmosphere and Volatile Evolution. We have used hybrid model and four-dimensional yield spectrum approach based on Monte Carlo simulation to calculate the ionization rate, limb intensity, and ion and electron densities of diffuse aurora due to precipitation of solar energetic particle and proton-hydrogen (H + -H) fluxes in the nighttime ionosphere of Mars. It is found that the production rates of atmospheric ions (CO 2 + , N 2 + , and O + ) are dominant in the upper ionosphere at about 100-150 km due to impact of H + -H. The solar energetic particle formed auroral ionosphere (CO 2 + , NO + , and O + ) in the middle ionosphere between 50 and 100 km due to precipitation of monoenergetic electrons of energies 25 to 100 keV. The simulated limb intensities of CO 2 + UVD due to impact of H + -H and auroral electrons are compared with Imaging Ultraviolet Spectrograph observations. Our model results are overestimating the observations, but 100 keV electrons deposited maximum energy around 75 km, closer to the observed altitude of the maximum emission. The densities of upper ionosphere (O 2 + , NO + , and CO 2 + ) due to impact of H + -H are smaller by one to two orders of magnitude than that produced by auroral electrons in the middle ionosphere.

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We have developed a seasonally dependent energy loss model to calculate the zonally averaged production rates of O 3 + due to impact of galactic cosmic rays in the dayside troposphere of Mars between solar longitudes (L s )~0°and 360°at low latitudes (2°N, 2°S, 25°N, and 25°S), midlatitudes (45°N and 45°S), and high latitudes (70°N and 70°S) in the Martian Year (MY) 28 and MY 29. We also represent the seasonal variability of zonally averaged ozone column density obtained from Mars Climate Database (MCD; Millour et al., 2014, https://hal.archives-ouvertes.fr/hal-01139592) during the daytime. These results are compared with the daytime observations of column ozone made by Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars onboard Mars Express (MEX). At mid-to-high latitudes ozone column density is maximum in northern winter and minimum in southern summer. At low-to-middle latitudes (2°N-S, 25°N-S, and 45°N-S), the production rates of O 3 + represent a broad peak between altitudes 26 and 45 km in both hemispheres. The peak production rates are increasing up to L s = 47.5°and then stabilized at about 2.5 × 10 −8 cm −3 /s. At L s ≥ 47.5°the peak production rate of O 3 + starts decreasing until it disappeared after L s = 127.5°. A major dust storm occurred in MY 28 at L s~2 80°in southern latitudes (~25°-35°S). During the dust storm period, dust opacity, ozone column density, and O 3 + production rate on the surface of Mars were increased by a factor of~3.