Energetic electron asymmetries at Mars: ASPERA-3 observations

Energetic electron fluxes from more than two years of ASPERA-3 observations are organized in different coordinate systems for the investigation of asymmetries in the global dynamics of the Martian magnetosphere. A clear asymmetry is found in the distribution of high-flux events with respect to the solar wind convective electric field (EswEsw) direction. These events are frequently detected below the average magnetic pile-up boundary (MPB) location at the terminator region of the hemisphere to which the EswEsw points and extend toward the tail. A detailed investigation of the electron fluxes at the terminator region also reveals that the largest contribution to this EswEsw asymmetry comes from locations of moderate or strong crustal fields. These observations have implications about reconnection processes in the terminator and provide new insight on magnetic anomaly effects in the global dynamics of the Mars–solar wind interaction.