Mars lacks a global dipole magnetic field like Earth. As a result, the solar wind and interplanetary magnetic field (IMF) directly interact with its upper atmosphere, generating an induced magnetosphere and driving ion escape from the red planet. As a key atmospheric loss process, understanding ion escape is essential for studies of atmospheric evolution and the long-term climate history of Mars. The NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission has been orbiting Mars since 2014 and has made extensive observations of the upper atmosphere and induced magnetosphere, providing more than a decade of invaluable data for investigating atmospheric loss. Using these observations, the average ion escape rates from present-day Mars, as well as their variability over a solar cycle, have been estimated. I will also talk about the different ion escape channels and acceleration processes, as well as how upstream solar radiation, solar wind, and IMF control the ion escape from Mars. These results provide insight into the dominant drivers of ion escape variability over the solar cycle and help constrain the historical atmospheric loss of Mars.
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