Abstract
Mars once had a dense atmosphere enabling liquid water existing on its
surface, however, much of that atmosphere has since escaped to space. We
examine how incoming solar and solar wind energy fluxes drive escape of
atomic and molecular oxygen ions (O+ and O2+) at Mars. We use MAVEN data
to evaluate ion escape from February 1, 2016 through May 25, 2022. We
find that Martian O+ and O2+ both have increased escape flux with
increased solar wind kinetic energy flux and this relationship is
generally logarithmic. Increased solar wind electromagnetic energy flux
also corresponds to increased O+ and O2+ escape flux,
however, increased solar wind electromagnetic energy flux seems to first
dampen ion escape until a threshold level is reached, at which point ion
escape increases with increasing electromagnetic energy flux. Increased
solar irradiance (both total and ionizing) does not obviously increase
escape of O+ and O2+. Our results suggest that the solar wind
electromagnetic energy flux should be considered along with the
kinetic
energy flux as an important driver of ion escape, and that other
parameters should be considered when evaluating solar irradiance’s
impact on O+ and O2+ escape.