2021/03/02 by Kamsali Nagaraja, Nagaraja, Kamsali, Praveen Kumar Basuvaraj +6
Physics and Astronomy · #Astro and Planetary Science #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Planetary Science and Exploration #Solar and Stellar Astrophysics (astro-ph.SR) #Space Physics (physics.space-ph) #Space Science and Extraterrestrial Life
paper · pdf · doi:10.48550/arxiv.2103.01930
openalex publication_date 2021/03/02 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
Since the first \in-situ measurements of the altitude profile of upper\natmospheric density and composition carried out by the Viking lander missions\nduring 1976, similar data were continuously gathered by MAVEN and MOM\nspacecraft orbiting Mars since September 2014 with a mass spectrometer and\nother related payloads. Using near-simultaneous observations by the two\norbiters, we show that both data sets confirm significant day-to-day variations\nof Argon (Ar) density profiles in the Martian thermosphere/exosphere during\n1-15 June 2018 when the solar EUV radiation did not show any appreciable\nchange. We extend this study to include the parent atmospheric constituents\n(CO2, Ar, He, N2) and the photochemical products (O, CO) to\nexamine the effect of solar wind plasma (e/H+) velocities and fluxes\nduring the above time interval. Density profiles of these constituents show\nsignificant effects due to the additional electron impact dissociation and\nionisation during the first week of June 2018, which subside in the next week\nreturning to normal conditions. These first-time results are interpreted based\non a number of relevant neutral and ion chemical reactions. This result\nprovides a vital input to future modelling efforts of Martian\nthermosphere/exosphere composition studies and the solar EUV related variations\ndue to the Schwabe cycle.\n