Fast spacecraft charging induced by a high-power electron beam emission and its mitigation through a plasma contactor

Abstract Active sounding experiments, including tracing magnetic field lines and magnetospheric sounding, may be accomplished in the GEO environment by the active emission of high-power electron beams. The continual emission of electron beam pulses during such experiments may result in the accumulation of positive charges on the spacecraft surface and a rise in the spacecraft potential, which might prohibit the normal emission of succeeding pulses. The plasma contactor has been shown to be a reliable method for neutralizing the spacecraft potential. But as the active charging effect brought on by the high-current electron beam manifests itself more quickly, it is still unknown whether the plasma contactor can reliably control the spacecraft potential in this circumstance. In this study, a two-dimensional PIC model is used to examine the active charging effect brought on by high-power electron beam emission. Findings indicate that the potential neutralization process may be affected by the ion sheath that forms close to the emitting surface of the plasma contactor, which cuts the electrical connection between the spacecraft and plasma in space. By evaluating the quantities and growth speeds of different particles during active charging, we discover that lowering the particle density or pre-emission time of the plasma contactor may bring the spacecraft potential to the equilibrium state. Additionally, the high-current electron beam raises the peak potential, making it more difficult to launch the electron beam properly before the spacecraft potential reaches equilibrium. In contrast, the high-energy electron beam is less susceptible to the active charging effect.