The influence of interplanetary magnetic field direction on Martian crustal magnetic field topology | CU Experts

Crustal magnetic fields influence a range of plasma processes at Mars,; guiding the flow of energy from the solar wind into the planet’s; atmosphere at some locations while shielding it at others. In this study; we investigate how these crustal fields vary with changes in the; direction of the incoming interplanetary magnetic field (IMF). Using; spacecraft measurements of electron flux and magnetic field, we analyze; magnetic topology throughout the Martian ionosphere for different IMF; configurations. We find that the topology of crustal field cusp regions; is dependent on IMF direction, and that cusps transition between open; and closed topology regularly as they rotate through the nightside of; Mars. Finally, we determine that cusps often become topologically closed; due to reconnection with open magnetic fields in the Martian; magnetotail, resulting in large day-to-night closed loops that could; represent a source of energy input into nightside crustal field regions.

Weber T; Brain DA; Xu S; Mitchell DL; Espley JR; Halekas JS; Mazelle C; Lillis RJ; DiBraccio GA; Jakosky BM

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