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

Shannon Curry (1) , Chuanfei Dong (2) , Janet Luhmann (1) , Yingjuan Ma (3) , Stephen Bougher (2) , Ronan Modolo (4) , François Leblanc (4)

1 SSL - Space Sciences Laboratory [Berkeley]
2 AOSS - Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor]
3 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
4 HELIOS - LATMOS

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.

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]

Shannon Curry, Chuanfei Dong, Janet Luhmann, Yingjuan Ma, Stephen Bougher, et al.. The Response of Heavy Planetary Ions at Mars to Reversals of the IMF. AGU Fall Meeting 2014, Dec 2014, San Francisco, United States. pp.P54A-08. ⟨hal-01113528⟩