  This observational study demonstrates that the magnitude and location of
energization of electrons in the Martian magnetosheath is more complex than
previous studies suggest. Electrons in Mars's magnetosheath originate in the
solar wind and are accelerated by an electric field when they cross the bow
shock. Assuming that this acceleration is localized solely to the shock, the
field-aligned electron distributions in the sheath are expected to be highly
asymmetric. However, such an asymmetry is not observed in this study. Based on
the analysis here, it is suggested that an additional parallel acceleration
takes place downstream of the Martian bow shock. This additional acceleration
suppresses the expected asymmetry of the electron distribution. Consequently,
along a flux tube in the magnetosheath that is tied on both ends to the bow
shock the difference in energization between parallel and anti-parallel
electrons is less than about 20 eV. Where this energization difference is
expected to be maximal, we find the energization difference to be at most 25%
of the predicted value.
