Mars heavy ion precipitating flux as measured by Mars Atmosphere and Volatile EvolutioN. Issue 21 (5th November 2015)

• Record Type: Journal Article
• Authors: Leblanc, F.; Modolo, R.; Curry, S.; Luhmann, J.; Lillis, R.; Chaufray, J. Y.; Hara, T.; McFadden, J.; Halekas, J.; Eparvier, F.; Larson, D.; Connerney, J.; Jakosky, B.
• Is Part Of: Geophysical research letters. Volume 42:Issue 21(2015:Nov.)
• Page Start: 9135
• Page End: 9141
• Publication Date: 2015-11-05
• Subjects: Mars -- atmosphere -- escape -- pickup ion -- sputtering; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2015GL066170
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: In the absence of an intrinsic dipole magnetic field, Mars' O + planetary ions are accelerated by the solar wind. Because of their large gyroradius, a population of these planetary ions can precipitate back into Mars' upper atmosphere with enough energy to eject neutrals into space via collision. This process, referred to as sputtering, may have been a dominant atmospheric loss process during earlier stages of our Sun. Yet until now, a limited number of observations have been possible; Analyzer of Space Plasmas and Energetic Atoms‐3/Mars Express observed such a precipitation only during extreme conditions, suggesting that sputtering might be not as intense as theoretically predicted. Here we describe one example of precipitation of heavy ions during quiet solar conditions. Between November 2014 and April 2015, the average precipitating flux is significant and in agreement with predictions. From these measured precipitating fluxes, we estimate that a maximum of 1.0 × 10 24 O/s could have been lost due to sputtering. Key Points: Precipitation of heavy picked up ions occurs at Mars First estimate of the intensity of the precipitating flux on a statistically significant base First calculation of the sputtered atmosphere based on this measurement