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Influence of Extreme Ultraviolet Irradiance Variations on the Precipitating Ion Flux From MAVEN Observations
Author(s) -
Martinez A.,
Leblanc F.,
Chaufray J. Y.,
Modolo R.,
Witasse O.,
Dong Y.,
Hara T.,
Halekas J.,
Lillis R.,
McFadden J.,
Eparvier F.,
Leclercq L.,
Luhmann J.,
Curry S.,
Titov D.,
Jakosky B.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl083595
Subject(s) - extreme ultraviolet lithography , flux (metallurgy) , extreme ultraviolet , mars exploration program , atmosphere of mars , atmosphere (unit) , atmospheric sciences , ion , solar wind , irradiance , physics , environmental science , materials science , plasma , astrobiology , meteorology , martian , optics , laser , quantum mechanics , metallurgy
We study the influence of the solar extreme ultraviolet (EUV) flux intensity on the precipitating ion fluxes as seen by the Solar Wind Ion Analyzer, an energy and angular ion spectrometer aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. We defined three periods with significantly different EUV flux intensity (1.6 and 3.2 times the lowest EUV intensity) and compare the precipitating ion flux measured by MAVEN/Solar Wind Ion Analyzer during each period. At low energy [30–650] eV, we find that the median (average) precipitating ion flux during the medium and low EUV periods are, respectively, 1.7 (2.1) and 3 (3.5) times more intense than the flux during the high EUV period. At high energy [650–25,000] eV, a similar trend in the intensity of the precipitating ion flux is observed but with an increase by 50% (46%) and 70% (79%), respectively. A larger EUV flux does therefore not seem to favor heavy ion precipitation into Mars's atmosphere, contrary to modeling prediction and overall expectations.