Electron Heating Associated with Spontaneous Hot Flow Anomaly at Mars

The Mars foreshock is populated by backstreaming particles that can generate a variety of foreshock transients and plasma waves. Using observations from Mars Atmosphere and Volatile EvolutioN (MAVEN) mission on 4 March 2018, we report a clear electron heating associated with a spontaneous hot flow anomalies (SHFAs) at Mars, accompanied by lower hybrid waves in the core region and a 1 Hz wave at the compression region. In the SHFA core region, the observed electron heating involves both adiabatic and non-adiabatic acceleration processes. In addition, the LHWs likely contribute to electron heating along the magnetic field and modulate both the electron energy flux and density. Within the compression region, the 1 Hz wave can efficiently scatter electrons, resulting in electron pitch angle distributions that become more isotropic. These results provide new insights into electron heating and the kinetic-scale wave-particle interactions associated with the SHFAs at Mars.