Coupling Effect of Electron Irradiation and Operating Voltage on the Deep Dielectric Charging Characteristics of Solar Array Drive Assembly

A deep dielectric charging model of a solar array drive assembly (SADA) under the coupling effect of electron irradiation and operating voltage is established based on the bipolar charge transport process. The distribution of space charge, potential and electric field in SADA are simulated and analyzed under three different operating conditions, i.e., flux model for internal charging (FLUMIC) spectrum electron irradiation acting alone; operating voltage acting alone; electron irradiation and operating voltage coupled. The effects of electron flux enhancement, electron direction, and operating voltage on charging properties are studied. Based on these investigations, discharge risk and location are pointed out. In the case of electrons incident from the end surface acting alone, much more space charge will accumulate than that from the columnar surface, and the maximum electric field will be above 108 V/m when the flux enhancement exceeds 100. When the operating voltage acts alone, the maximum electric field will not exceed 107 V/m as long as the operating voltage is below 8772 V. Under typical spectrum, the maximum electric field under coupling effect increases linearly as the operating voltage increases. When the electron flux enhancement increases to 100 and 1000, the electron irradiation dominates the deep charging characteristic. This provides theoretical guidance for the methods of discharge containment in SADAs.