Atmospheric escape from Mars and its relation to habitability

Presenter: Kanako SEKI
Atmosphere escape from Mars to space is one of important problems to understand drastic climate change of the ancient Mars from a wet habitable environment to the dry current one. The geological studies suggest that the climate change occurred from 4 to 3.5 billion years (Ga) ago. It is known that the time period interestingly corresponds to the period just after the ancient Mars lost its global intrinsic field between 4 and 4.1 Ga ago. Observations by NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) have provided new insights about the atmospheric escape processes in operation at Mars. Among them, the cold ion escape is a promising candidate to enable a large number of heavy ions to escape from the ionosphere. This presentation aims at providing an overview of the recent progress in understanding of the atmospheric escape mechanisms from Mars brought by combinations of observations and global MHD (magnetohydrodynamic) simulations of solar wind-Mars interactions.