Impact of Martian Crustal Magnetic Field on the Ion Escape. Issue 10 (12th October 2020)

• Record Type: Journal Article
• Authors: Dubinin, E.; Fraenz, M.; Pätzold, M.; Woch, J.; McFadden, J.; Fan, K.; Wei, Y.; Tsareva, O.; Zelenyi, L.
• Is Part Of: Journal of geophysical research. Volume 125:Issue 10(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-12
• Subjects: Mars -- crustal magnetic fields -- ion escape -- ionosphere -- solar wind -- MAVEN; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2020JA028010
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Based on the Mars Atmosphere and Volatile EvolutioN (MAVEN) observations, we have analyzed the role of the crustal magnetic field on ion loss driven by the direct interaction of the solar wind with the Mars ionosphere. Crustal magnetic fields significantly attenuate the ion ionospheric motions and raise the flux of returning ions. On the other hand, since the ion densities in the ionosphere with strong crustal field are significantly higher than in the ionosphere with a weak crustal magnetic field, the net escape fluxes from the ionosphere with the crustal sources remain vital. The crustal magnetic field also leads to the expansion of the ionosphere and increase of the area exposed to solar wind. As a result, fluxes from higher altitudes essentially contribute to the flow pattern in Martian tail producing an excess of ion loss rate (∼15%) through the southern part of the tail. Thus, effects of inhibition and enhancement of the escape rate by the crustal magnetic field at Mars operate in competition producing a minor influence on the total ion loss. Key Points: Crustal magnetic field at Mars has a twofold effect on atmospheric erosion At lower altitudes the crustal fields form a protective shield around the ionized atmosphere Due to expansion of ionosphere to higher altitudes, a larger cross‐section area is exposed to the solar wind that increases ion losses