The role of plasma contactors in mitigating rapid spacecraft charging during emitting electron beam pulses

During electron beam sounding experiments, the emission of electron beam pulses can result in a continuous increase in spacecraft potential, impeding the normal emission of subsequent pulses. Plasma contactors can mitigate the increase in spacecraft potential through “ion emission”, but whether they are effective in addressing the active charging effect of high-current electron beam pulses remains uncertain. This paper employs the PIC method to explore the ion sheath occurring on the contactor emitting surface after increasing the electron beam current, along with its influence on spacecraft potential. A key emphasis is placed on contrasting the intrinsic connection between the contactor characteristic parameters and spacecraft potential variation during continuous emission and pulse emission with different pulse widths. Ultimately, an analysis is conducted on the variation of optimal contactor characteristic parameters with changes in the beam current. The research findings of this paper indicate that suppressing the pulse active charging effect necessitates thorough consideration of the impact of the contactor electron quantity on the ion sheath. Reducing the electron beam pulse width while correspondingly adjusting the contactor pre-emission time and current can effectively prolong the stable emission duration of electron beam pulses.