Effects of Global and Regional Dust Storms on the Martian Hot O Corona and Photochemical Loss. Issue 4 (27th March 2020)

• Record Type: Journal Article
• Authors: Lee, Yuni; Fang, Xiaohua; Gacesa, Marko; Ma, Yingjuan; Tenishev, Valeriy; Mahaffy, Paul; Dong, Chuanfei; Combi, Michael; Bougher, Stephen; Jakosky, Bruce
• Is Part Of: Journal of geophysical research. Volume 125:Issue 4(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-27
• Subjects: Mars -- photochemical escape -- Monte Carlo model -- hot O corona -- exosphere -- dust storm; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA027115
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: We examine here for the first time the effects of both global and regional dust storms on the formation of the Martian hot O corona and associated photochemical loss of O. Our study is conducted by utilizing our integrated model framework, which couples our Martian hot O corona model with a multifluid magnetohydrodynamic model for Mars for the dusty and clear atmospheric condition cases. We present our results with the most up‐to‐date cross sections for the O( 3 P )‐CO2 collisions. The main effect of dust storms on the ionosphere is the upward shift of the ionosphere on the dayside, which results in an increase in production of hot O at all altitudes above the ionospheric peak. However, the dust‐induced inflation of the neutral upper atmosphere results in an enhancement in collisional loss of hot O and thus effectively suppresses the hot O density, reducing the global photochemical loss rate by ~28% for the global dust storm scenario. The relative density structure of the hot O corona does not show any significant changes, while its magnitude decreases at all altitudes. Key Points: We investigated the effect of dust storms on photochemical escape from Mars using up‐to‐date cross sections for O‐CO2 collisions The storm‐induced upward shift of the ionosphere causes increased production of hot O and efficient thermalization occurs by the inflated thermosphere The net result is a global photochemical escape rate that is suppressed by ~28% during the global dust storm scenario