LPL Colloquium: Dr. Yingjuan Ma
Time-dependent Global MHD Studies of the Solar Wind Interaction with Mars
University of California, Los Angeles
Mars has only localized crustal magnetic fields, so the solar wind plasma flow interacts directly with the Mars atmosphere/ionosphere system, which generates induced current in the ionosphere and modifies the magnetic field environment around Mars. Here we use a 3D time-dependent multi-spices single-fluid MHD model to understand the plasma environment of Mars. The effects of the crustal magnetic field are discussed based on model result and its comparison with MGS (Mars Global Surveyor) magnetometer observations. Two event studies of MAVEN (Mars Atmosphere and Volatile Evolution) mission will also be presented, one for quiet solar wind condition and the other for a strong ICME impact on March 2015. The ongoing MAVEN mission was designed to study the upper atmosphere, ionosphere, and magnetosphere of Mars, the response to solar and solar-wind input, and the ability of atmospheric molecules and atoms to escape to space. Through detailed comparisons between the model results and the relevant plasma observations from MAVEN, we find that the time-dependent global MHD model is able to reproduce the main features of the plasma environment around Mars during both quiet and disturbed solar wind conditions. Model results suggest that the total ion escape rate was enhanced by an order of magnitude during the ICME event, indicating space weather could have a significant impact on the total ion escape during Martian history.