Journal article
On the Origins of Mars' Exospheric Nonthermal Oxygen Component as Observed by MAVEN and Modeled by HELIOSARES
Journal of geophysical research. Planets, Vol.122(12), pp.2401-2428
12/2017
DOI: 10.1002/2017JE005336
Abstract
The first measurements of the emission brightness of the oxygen atomic exosphere by Mars Atmosphere and Volatile EvolutioN (MAVEN) mission have clearly shown that it is composed of a thermal component produced by the extension of the upper atmosphere and of a non-thermal component. Modeling these measurements allows us to constrain the origins of the exospheric O and, as a consequence, to estimate Mars' present oxygen escape rate. We here propose an analysis of three periods of MAVEN observations based on a set of three coupled models: a hybrid magnetospheric model (LatHyS), an Exospheric General Model (EGM) and the Global Martian Circulation model of the Laboratoire de Météorologie Dynamique (LMD-GCM), which provide a description of Mars' environment from the surface up to the solar wind. The simulated magnetosphere by LatHyS is in good agreement with MAVEN Plasma and Field Package instruments data. The LMD-GCM modeled upper atmospheric profiles for the main neutral and ion species are compared to NGIMS/MAVEN data showing that the LMD-GCM can provide a satisfactory global view of Mars' upper atmosphere. Finally, we were able to reconstruct the expected emission brightness intensity from the oxygen exosphere using EGM. The good agreement with the averaged measured profiles by IUVS during these three periods suggests that Mars' exospheric non-thermal component can be fully explained by the reactions of dissociative recombination of the O2+ ion in Mars' ionosphere, limiting significantly our ability to extract information from MAVEN observations of the O exosphere on other non-thermal processes, such as sputtering.
Details
- Title: Subtitle
- On the Origins of Mars' Exospheric Nonthermal Oxygen Component as Observed by MAVEN and Modeled by HELIOSARES
- Creators
- François Leblanc - Université Paris CitéJean-Yves Chaufray - Laboratoire atmosphères, milieux, observations spatialesRonan Modolo - University of Paris-SaclayLudivine Leclercq - University of VirginiaS. Curry - University of California, BerkeleyJ. Luhmann - University of California, BerkeleyR. Lillis - University of California, BerkeleyT. Hara - University of California, BerkeleyJ. Mcfadden - University of California, BerkeleyJ. Halekas - University of IowaN. Schneider - University of Colorado BoulderJustin Deighan - University of Colorado BoulderP. R. Mahaffy - Goddard Space Flight CenterM. Benna - Goddard Space Flight CenterR. E. Johnson - University of VirginiaF. Gonzalez-Galindo - Instituto de Astrofísica de AndalucíaFrançois Forget - Laboratoire de Météorologie DynamiqueM. A. López-Valverde - Instituto de Astrofísica de AndalucíaF. G. Eparvier - Laboratory for Atmospheric and Space PhysicsB. Jakosky - Laboratory for Atmospheric and Space Physics
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Planets, Vol.122(12), pp.2401-2428
- Publisher
- Wiley-Blackwell
- DOI
- 10.1002/2017JE005336
- ISSN
- 2169-9097
- eISSN
- 2169-9100
- Grant note
- DOI: 10.13039/501100001665, name: Agence Nationale de la Recherche, award: ANR‐09‐BLAN‐0223
- Language
- English
- Date published
- 12/2017
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428788302771
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