Collaborative Research: Global Response of the Martian Thermosphere to Energetic Pickup Ions

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

AST-0908472/0908311 Fang/Liemohn This collaborative project will apply coupled state-of-the-art numerical models to consider the global response of the Martian thermosphere to energetic pickup ions. In particular, the research will study the bombardment effects of oxygen ions on composition and energetics. The neutral constituents of the atmospheric corona can be ionized, picked up by the solar wind, and ultimately returned to interact with the atmosphere, causing neutral particles to escape from Mars. This sputtering loss and associated heating effects have not yet been included in any global models to consider the coupling among the Mars system components. This project will treat the Mars environment as a single system, including pickup ions within the mass and energy budget of the Martian thermosphere. The work will apply a magneto-hydrodynamics field-based pickup ion transport model, along with a different model for the interaction between incident energetic particles and the thermosphere below the exobase, and build the sputtering and heating effects into the state-of-the-art Mars Thermosphere General Circulation Model. The escape rate estimate for direct pickup ion loss and sputtering loss will be used to advance understanding of the non-thermal processes governing atmospheric erosion, and the quantification of long-term atmospheric evolution. This work will permit extrapolation of the history of the Martian atmosphere and climate, the possible presence of liquid water, and planetary habitability. Comparison with spacecraft measurements will constrain understanding of the Mars-solar wind interaction. The results will be important for future Mars probe spacecraft, and the research involves graduate students. For the broader community, Mars sciences capture the excitement of scientific exploration and adventure. Because this project helps to understand oxygen loss and thus water loss, it provides an ideal opportunity to advance scientific literacy through the public interest in water, and perhaps life, on Mars.