Martian crustal field influence on O+ and O2+ escape as measured by MAVEN | CU Experts

Martian crustal magnetic fields influence the solar wind interaction; with Mars in a way that is not fully understood. In some locations,; crustal magnetic fields act as “mini-magnetospheres”, shielding the; planet’s atmosphere, while in other locations they act as channels for; enhanced energy input and particle escape. The net effect of this system; is not intuitively clear, but previous modeling studies have suggested; that crustal fields likely decrease global ion escape from Mars. In this; study we use data from the Mars Atmosphere and Volatile EvolutioN; (MAVEN) spacecraft to analyze how crustal magnetic fields influence both; global and local ion escape at Mars. We find that crustal fields only; increase ion escape if ions are assumed to be so unmagnetized that; closed magnetic fields only trap 35% or less of energized Oxygen ions.; In any other case, crustal fields decrease both global and local ion; escape by as much as 40% and 80%, respectively. This suggests that the; presence of crustal magnetic fields has had a moderate impact on; atmospheric ion loss throughout Martian history, potentially influencing; the planet’s atmospheric evolution and habitability.

Weber T; Brain DA; Xu S; Mitchell DL; Espley J; Mazelle C; Mcfadden JP; Jakosky BM

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