Statistical Comparative Analysis of Plasma Depletion and Electron Energy Flux Depletion in the Martian Ionosphere: Observations From MAVEN Spacecraft

Plasma depletion and electron energy flux depletion are key phenomena that contribute to the understanding of plasma escape in the Martian ionosphere. Based on electron energy flux and ion measurements obtained from the Mars Atmosphere and Volatile Evolution spacecraft from 1 October 2014 to 31 December 2023, this study analyzes the climatic characteristics of plasma depletion and electron energy flux depletion in the Martian ionosphere. The observations reveal that the plasma depletion and electron energy flux depletion are frequently observed in regions with Martian crustal magnetic fields. Electron energy flux depletion occurs approximately 2–5 times more often than the plasma depletion. In terms of the distribution of altitude of the two depletions, the observations show that the electron energy flux depletions mainly occur below 200 km, while the plasma depletions dominate 200–350 km. Additionally, the two types of depletion both exhibit variations with the local time, which shows a higher occurrence rate at night than during the day. Plasma depletion exhibits minimal seasonal variability, whereas electron energy flux depletion displays a pronounced seasonal pattern with peak occurrences near mid‐season and reduced activity at the beginning and end. Moreover, simultaneous plasma and electron energy flux depletions occur both at day and night, with a higher frequency at night concentrated over Martian crustal magnetic field regions. Several mechanisms that could contribute to the formation of the depletion are analyzed and discussed.