P21A-2089
Consequences of simulated ion precipitation and sputtering during extreme conditions at Mars: comparison to MAVEN observations
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Shannon Curry1, Janet G Luhmann2, Chuanfei Dong3, Francois Leblanc4, Ronan Modolo4, James P McFadden2, Yingjuan Ma5, Dave A Brain6, Jasper S Halekas7, John E P Connerney8, Jared R Espley8, Yuki Harada1 and Takuya Hara1, (1)Space Sciences Laboratory, Berkeley, CA, United States, (2)University of California Berkeley, Berkeley, CA, United States, (3)University of Michigan Ann Arbor, Ann Arbor, MI, United States, (4)LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales, Paris Cedex 05, France, (5)University of California Los Angeles, Los Angeles, CA, United States, (6)University of Colorado at Boulder, Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (7)University of Iowa, Physics and Astronomy, Iowa City, IA, United States, (8)NASA Goddard Space Flight Center, Greenbelt, MD, United States
Abstract:
Mars lacks an intrinsic dipole magnetic field, creating a scenario where the solar wind directly interacts with the upper atmosphere and newly created ions can be picked up and swept away by the background convection electric field. These pick-up ions can directly escape or precipitate back into the atmosphere and induce atmospheric sputtering of neutrals. Sputtering is believed to be one of the main drivers of atmospheric escape during the early epochs of our solar system when the solar activity and EUV intensities were much higher than the present day. Using the March 8th ICME event and other extreme solar wind events, we simulate three phases of the Mars-solar wind interaction using fluid and kinetic models and compare the predicted heavy ion precipitation with MAVEN observations in order to derive heavy ion precipitation and the first set of data-based sputtering rates. The fluid model reproduces the observed features in the solar wind density, velocity and magnetic field seen along the MAVEN orbit during the March 8th ICME event, and the subsequent precipitation shows strong agreement with other published predictions of sputtering in extreme conditions.
