Mars: Determination of the most appropriate electron energy for the bow shock identification, using MGS data

Abstract

The bow shock of Mars is re‐examined using combined magnetic field and electron flux data obtained by the Mars Global Surveyor during 1998. The location of the bow shock, seems to depend on the actual energy chosen when the electron flux is used as a diagnostic tool. We compare the electron data from 4 different energy channels to the corresponding magnetic field data, in order to determine the most accurate electron energy for the identification of the exact bow shock location, in the lack of magnetic field measurements (eg. Mars Express mission). The results show that the location of the bow shock can be accurately detected by using electron energy channels from 50 up to 200 eV. The planetocentric difference between the magnetic and electron flux configuration of the bow shock was found to be small, compared to the scale of the Martian magnetosphere. This difference in most cases was found to be comparable to the actual thickness of the bow shock (∼70 km). A systematic delay at the detection time betwee...