Characterization of Jason-3 Spacecraft Surface Charging in LEO Polar Regions From AMBER Observations

We have characterized spacecraft charging events in low Earth orbit (LEO) polar regions with the Active Monitor Box of Electrostatic Risk (AMBER) instrument onboard the Joint Altimetry Satellite Oceanography Network—3 (Jason-3) ocean topography mission for the first time for this spacecraft. AMBER data, taken at an altitude of 1336 km, over the period January 2017–March 2020, with measurements recorded close to the current solar minimum have been analyzed, using systematic filtering of ions spectrograms with selected threshold energies and time windows to detect negative spacecraft charging events; 109 spacecraft charging events were found. The events are examined visually and characterized by their spatial and temporal location, duration, and intensity (e.g., spacecraft potential). At the Jason-3 altitude (1336 km), the ion signature predominately lasts under 30 s in conjunction with auroral inverted V crossings, while intense fluxes of electrons corresponding to the encounter of the discrete auroral region last between 30 s and 1 min. Most of the detected spacecraft charging events show charging levels between −30 and −1000 V. The spacecraft charging events are located in the magnetic local time (MLT) sector 17h–05h, predominately before midnight. The distribution is equal between the northern and southern hemispheres. We found a high correlation between the charging time profile and that of the auroral electron average energy and energy flux along the satellite path. Overall statistics over three years as well as different event morphologies, electron spectra, and comparisons to worst case electron flux spectral distributions are presented and discussed.