Since the first \emph{in-situ} measurements of the altitude profile of upper atmospheric density and composition carried out by the Viking lander missions during 1976, similar data were continuously gathered by MAVEN and MOM spacecraft orbiting Mars since September 2014 with a mass spectrometer and other related payloads. Using near-simultaneous observations by the two orbiters, we show that both data sets confirm significant day-to-day variations of Argon ($Ar$) density profiles in the Martian thermosphere/exosphere during 1-15 June 2018 when the solar EUV radiation did not show any appreciable change. We extend this study to include the parent atmospheric constituents ($CO_{2}$, $Ar$, $He$, $N_{2}$) and the photochemical products ($O$, $CO$) to examine the effect of solar wind plasma ($e/H^{+}$) velocities and fluxes during the above time interval. Density profiles of these constituents show significant effects due to the additional electron impact dissociation and ionisation during the first week of June 2018, which subside in the next week returning to normal conditions. These first-time results are interpreted based on a number of relevant neutral and ion chemical reactions. This result provides a vital input to future modelling efforts of Martian thermosphere/exosphere composition studies and the solar EUV related variations due to the Schwabe cycle.
High-Latitude Zonal Jets in the Martian Upper Atmosphere Driven by Non-Orographic Gravity Waves
Sorbonne Université（索邦大学）；École Polytechnique（巴黎综合理工学院）；Institut Polytechnique de Paris（巴黎理工学院）；CNRS（法国国家科学研究中心）；Instituto de Astrofisica de Andalucia（安达卢西亚天体物理研究所）；LATMOS/IPSL（大气、空间和环境研究实验室/地球物理与行星系统研究所）；Université d’Orléans（奥尔良大学）
Impacting the dayside Martian ionosphere from above and below: Effects of the impact of CIRs and ICMEs close to aphelion (April 2021) and during dust storms (June-July 2022) seen with MAVEN ROSE
