31st Annual Meeting of the DPS, October 1999
Session 72. Mars Atmosphere: Chemistry II
Contributed Oral Parallel Session, Friday, October 15, 1999, 2:00-2:40pm, Sala Plenaria

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[72.04] Sputtering of Mars Atmosphere by O+ Pick-up Ions: New Insights

F. Leblanc, R.E. Johnson (Engineering Physics, University of Virginia, Charlottesville), J. Luhmann (Spaces Sciences Laboratory, University of California, Berkeley), S. H. Brecht (Bay Area Research Corporation, Orinda, California), M. Wong (AER Corporation, Memorial Drive, Cambridge)

We calculate the sputtering of an O thermosphere by incident O+ ions using a Direct Simulation Monte Carlo method (DSMC) for a 2-D representation of the Mars atmosphere. The calculations are carried out for a number of possible pick-up ions fluxes corresponding to different solar intensities. The goal here is to consider the loss of atmosphere in earlier epochs when the Mars thermosphere was dominated by neutral oxygen atoms. The sputter-produced ejecta and enhanced population of the corona generated by the incident pick-up ions will be described: their spatial and energy distributions at each solar intensity. These results will be compared to those from the standard 1-D atmospheric sputtering calculations and will be used to estimate the effect of feedback processes on the sputter-induced loss of atmosphere on Mars.

The author(s) of this abstract have provided an email address for comments about the abstract: fl3x@virginia.edu

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