Abstract
We investigate sunward planetary ions in the Martian magnetotail that
potentially reduce the amount of escaping ions. The global properties of
sunward flows in the Martian magnetotail are characterized, based on
over 13-years of ion data (May 2007–December 2020) collected by the
ASPERA-3 instrument on Mars Express. We find that sunward flows mainly
occur in the vicinity of the crustal fields, implying that crustal
fields may play a key role in producing such flows. The occurrence rate
and sunward flux are higher during solar maximum rather than solar
minimum. However, we identify a relatively low occurrence rate of
sunward flows and low sunward flux, suggesting that sunward flows have
negligible influence on total ion escape at Mars. This is different from
those at Venus, where sunward flows can significantly decrease the total
escape rates of ions.