Journal article
Proton cyclotron waves occurrence rate upstream from Mars observed by MAVEN: associated variability of the Martian upper atmosphere
Journal of geophysical research. Space physics, Vol.121(11), pp.11,113–11,128-11,128
2016
DOI: 10.1002/2016JA023270
Abstract
Measurements provided by the Magnetometer and the Extreme Ultraviolet Monitor (EUVM) onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft together with atomic H exospheric densities derived from numerical simulations are studied for the time interval from October 2014 up to March 2016. We determine the proton cyclotron waves (PCWs) occurrence rate observed upstream from Mars at different times. We also study the relationship with temporal variabilities of the high altitude Martian hydrogen exosphere and the solar EUV flux reaching the Martian environment. We find that the abundance of PCWs is higher when Mars is close to perihelion, and decreases to lower and approximately constant values after the Martian Northern Spring Equinox. We also conclude that these variabilities cannot be associated with biases in MAVEN's spatial coverage or changes in the background magnetic field orientation. Higher H exospheric densities on the Martian day side are also found when Mars is closer to perihelion, as a result of changes in the thermospheric response to variability in the ultraviolet flux reaching Mars at different orbital distances. A consistent behavior is also observed in the analyzed daily irradiances measured by the MAVEN EUVM. The latter trends point towards an increase in the planetary proton densities upstream from the Martian bow shock near perihelion. These results then suggest a method to indirectly monitor the variability of the H exosphere up to very high altitudes during large time intervals (compared to direct measurements of neutral particles), based on the observed abundance of PCWs.
Details
- Title: Subtitle
- Proton cyclotron waves occurrence rate upstream from Mars observed by MAVEN: associated variability of the Martian upper atmosphere
- Creators
- Norberto Romanelli - Université Toulouse III - Paul SabatierChristian Mazelle - Centre National pour la Recherche Scientifique et Technique (CNRST)Jean-Yves Chaufray - Laboratoire atmosphères, milieux, observations spatialesKarim Meziane - University of New BrunswickLican Shan - Chinese Academy of SciencesSuranga Ruhunusiri - University of IowaJack E. P Connerney - Goddard Space Flight CenterJared R Espley - Goddard Space Flight CenterFrancis Eparvier - University of Colorado BoulderEdward M. B Thiemann - Laboratory for Atmospheric and Space PhysicsJasper S Halekas - University of IowaDavid L Mitchell - University of California, BerkeleyJames P Mcfadden - University of California, BerkeleyDavid Brain - University of Colorado BoulderBruce M Jakosky - University of Colorado Boulder
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.121(11), pp.11,113–11,128-11,128
- Publisher
- American Geophysical Union/Wiley
- DOI
- 10.1002/2016JA023270
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Grant note
- DOI: 10.13039/501100002830, name: Centre National d’Etudes Spatiales
- Language
- English
- Date published
- 2016
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199958802771
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