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A comparison of global models for the solar wind interaction with Mars |
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| Authors: | D Brain S Barabash S Bougher G Chanteur E Dubinin M Fraenz E Harnett E Kallio S Ledvina K Liu Y Ma A Nagy H Nilsson S Simon |
| Institution: | a University of California, UC Berkeley Space Sciences Lab, 7 Gauss Way, Berkeley, CA 94720, USA b Swedish Institute of Space Physics, Kiruna, Sweden c Institute for Theoretical Physics, TU Braunschweig, Germany d Atmospheric, Oceanic, and Space Sciences Department, University of Michigan, Ann Arbor, MI, USA e Bay Area Research Corporation, Orinda, CA, USA f CETP-IPSL, 10-12 avenue de l’Europe, 78140, Vélizy, France g Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA h Max-Planck-Institut für Aeronomie, Katlenburg-Lindau, Germany i Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, CO, USA j Department of Earth and Space Sciences, University of Washington, Seattle, WA, USA k Finnish Meteorological Institute, Helsinki, Finland l Space Research Institute, Austrian Academy of Sciences, Austria m Institute for Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA n Swedish Institute of Space Physics, Uppsala, Sweden o LAMTOS/IPSL/UVSQ, 10-12 avenue de l’Europe, 78140, Vélizy, France p National Institute of Information and Communications Technology, Tokyo, Japan q CREST, Japan Science and Technology Agency, Saitama, Japan r Institute of Geophysics and Meteorology, University of Cologne, Cologne, Germany |
| Abstract: | We present initial results from the first community-wide effort to compare global plasma interaction model results for Mars. Seven modeling groups participated in this activity, using MHD, multi-fluid, and hybrid assumptions in their simulations. Moderate solar wind and solar EUV conditions were chosen, and the conditions were implemented in the models and run to steady state. Model output was compared in three ways to determine how pressure was partitioned and conserved in each model, the location and asymmetry of plasma boundaries and pathways for planetary ion escape, and the total escape flux of planetary oxygen ions. The two participating MHD models provided similar results, while the five sets of multi-fluid and hybrid results were different in many ways. All hybrid results, however, showed two main channels for oxygen ion escape (a pickup ion ‘plume’ in the hemisphere toward which the solar wind convection electric field is directed, and a channel in the opposite hemisphere of the central magnetotail), while the MHD models showed one (a roughly symmetric channel in the central magnetotail). Most models showed a transition from an upstream region dominated by plasma dynamic pressure to a magnetosheath region dominated by thermal pressure to a low altitude region dominated by magnetic pressure. However, calculated escape rates for a single ion species varied by roughly an order of magnitude for similar input conditions, suggesting that the uncertainties in both the current and integrated escape over martian history as determined by models are large. These uncertainties are in addition to those associated with the evolution of the Sun, the martian dynamo, and the early atmosphere, highlighting the challenges we face in constructing Mars’ past using models. |
| Keywords: | Mars Solar wind Ionospheres Atmospheres Evolution |
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