Three‐Dimensional Configuration of Induced Magnetic Fields Around Mars
Chi Zhang, Zhaojin Rong, Lucy Klinger, H. Nilsson, Zhen Shi, Fei He, Jiawei Gao, Xinzhou Li, Yoshifumi Futaana, Robin Ramstad, Xiao‐Dong Wang, Mats Holmström, S. Barabash, Kai Fan, Yong Wei
Abstract
Abstract Using over 6 years of magnetic field data (October 2014–December 2020) collected by the Mars Atmosphere and Volatile EvolutioN, we conduct a statistical study on the three‐dimensional average magnetic field structure around Mars. We find that this magnetic field structure conforms to the pattern typical of an induced magnetosphere, that is, the interplanetary magnetic field (IMF) which is carried by the solar wind and which drapes, piles up, slips around the planet, and eventually forms a tail in the wake. The draped field lines from both hemispheres along the direction of the solar wind electric field ( E ) are directed toward the nightside magnetic equatorial plane, indicating that they are “sinking” toward the wake. These “sinking” field lines from the +E‐hemisphere ( E pointing away from the plane) are more flared and dominant in the tail, while the field lines from the –E‐hemisphere ( E pointing toward) are more stretched and “pinched” toward the plasma sheet. Such highly “pinched” field lines even form a loop over the pole of the –E‐hemisphere. The tail current sheet also shows an E‐asymmetry: the sheet is thicker with a stronger tailward force at +E‐flank, but much thinner and with a weaker (even turns sunward) at –E‐flank. Additionally, we find that IMF B x can induce a kink‐like field structure at the boundary layer; the field strength is globally enhanced and the field lines flare less during high dynamic pressure.