Mars heavy ion precipitating flux as measured by MAVEN

Abstract:

Mars’ atmospheric escape induced by heavy planetary ions accelerated by the solar wind and reimpacting Mars’ atmosphere has been suggested to occur. The sputtering of Mars’ atmosphere has been even suggested to lead to a significant cumulated loss along Mars’ history. Up to now, only a limited number of observations have been possible. ASPERA-3/Mars Express observed such precipitation only during extreme solar conditions events suggesting that sputtering might be not as intense as theoretically predicted.

Based on MAVEN first six months of observations, we here show that precipitation of heavy ions also occur during quiet solar conditions and that the average precipitating flux during this period is significant and globally in good agreement with predictions. From these measured precipitating flux, we propose a first estimate of the atmospheric escape induced by sputtering. Up to 8.8×10⁵ O/cm²/s was lost by Mars’ atmosphere between November 2014 and April 2015.