Theory of spacecraft potential jump in geosynchronous plasma

For disturbed geosynchronous plasma, the onset of spacecraft charging and its evolution become more complex than quiet environment. A sudden jump of spacecraft potential can occur in specific environment conditions which can be detrimental to onboard electronics. In this paper, the potential jump for geosynchronous spacecraft charging is theoretically modeled and comprehensively characterized. Two types of potential jump in opposite directions are elucidated, and the threshold conditions for both types of jump are determined. At both thresholds, the spacecraft potentials are semisteady, but in opposite directions, with the possibility of a jump to a stable potential. The polarity of movement across the thresholds from different plasma will cause a spacecraft to experience irreversible charging histories which result in significant hysteresis. Generally, the jump to negative potential occurs with greater magnitude as compared to a potential jump in positive direction. Ion distribution has negligible influence to the threshold condition for jump to negative potential. However, ion distribution significantly affects the threshold for jump to positive potential and subsequently modifies the parametric domains of spacecraft charging.