Statistical studies on Mars atmospheric sputtering by precipitating pickup O⁺: Preparation for the MAVEN mission

With the upcoming MAVEN mission, the role of escape in the evolution of the Martian atmosphere is investigated in more detail. This work builds on our previous modeling of the atmospheric impact of the pickup O⁺ sputtering effects for various solar wind parameters, solar EUV intensities, and the surface crustal field distributions. Relationships between the incident ion properties and the ejected hot neutral components, often referred to as atmospheric sputtering, are derived for application to proposed MAVEN ion spectrometer measurements of precipitating O⁺. We show how our simulation results can be used to constrain the sputtering effects under present conditions and to interpolate toward estimates of sputtering efficiencies occurring in earlier epochs. Present-day sputtering under typical circumstance is estimated to be weak but possibly detectable as an exospheric enhancement. The ultimate goal of estimating the importance of atmospheric sputtering effects on the evolution of the Martian atmosphere can be better deduced by the combining MAVEN measurements with models and the sputtering response relations derived here.