The Response of Heavy Planetary Ions at Mars to Reversals of the IMF

Friday, 19 December 2014: 5:45 PM
Shannon Curry1, Chuanfei Dong2, Janet G Luhmann3, Yingjuan Ma4, Stephen W Bougher2, Ronan Modolo5 and Francois Leblanc5, (1)Space Sciences Laboratory, Berkeley, CA, United States, (2)AOSS, Ann Arbor,, MI, United States, (3)University of California Berkeley, Berkeley, CA, United States, (4)University of California Los Angeles, Los Angeles, CA, United States, (5)LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales, Paris Cedex 05, France
We present a kinetic study to quantify the response of Mars’ atmosphere to changes in the interplanetary magnetic field (IMF) configuration, specifically with respect to the escape rate of the atmosphere. Because Mars lacks a dipole magnetic field, the solar wind directly interacts with the upper neutral atmosphere to create ‘pick-up’ ions. We will present global maps of escaping O+ pick up ions during different solar cycle phases for multiple IMF conditions using a magnetohydrodynamic (MHD) and test particle simulation. This study also examines the role of the crustal fields for the different IMF configurations; the remanent crustal magnetic fields, especially in extreme conditions, influence the magnetic topology at Mars and subsequently drive changes in heavy ion atmospheric escape. The results indicate that the escape rate from Mars’ atmosphere can change over an order of magnitude due to the IMF, solar cycle, and crustal field orientation, directly impacting Mars’ climate and our understanding of the processes that influence atmospheric evolution. These results directly support MAVEN, the next Mars Scout, whose primary objective is to understand the evolution of Mars’ atmosphere.