摘要:
“快速充电事件”是国际空间站2006年首次观测到的一种充电现象，在出地影瞬间的1-3 s内航天器结构体被迅速充到?30-?70 V的负电位，显著超过空间站的安全设计标准，一度引起国际航天界的关注。目前国际上对“快速带电”的研究尚不充分。基于Furguson等的研究，本文建立了快速充电的物理模型，对快速充电的机理和规律给出了合理的解释。计算及分析结果表明：快速充电是在航天器出地影瞬间由高压太阳电池阵的光伏激发过程驱动的，是一种非平衡态的充电过程；快速充电脉冲主要是由于在太阳帆板电压的快速启动过程中帆板上的电子充电电流未及时被玻璃盖片的充电所阻塞而导致的，当快速充电过程达到平衡时便表现为“正常充电事件”；快速充电的幅度主要取决于太阳帆板电压的启动时间、启动方式等，因此表现出一定的离散性，但随着等离子体密度的增大而衰减，与国际空间站观测结果一致。
Abstract:
The rapidly charging event (RCE) is a new category of spacecraft charging, which was first observed at an international space station in 2006. It occurred in the presence of the eclipse, with the floating potential increasing abruptly to tens of volts, well beyond the safety level of?40 V, within a few seconds. The RCE has not yet been understood thoroughly until now. Based on Ferguson and Craven’s theory, we developed a physical model for the rapidly charging events recently and gave satisfactory predictions compared with the observations. In this paper, we investigate the physical process and mechanism in detail, and explain the statistical charac-teristics and the underlying physics through the model calculations. It is shown that the rapidly charging event is a non-equilibrium charging process and driven by the high voltage solar arrays. The rapid charging is mainly due to the fact that the cover glass blocking effect cannot follow the rapid increasing of the solar voltage when it is abruptly turned on at the exit of eclipse. As the RCE reaches equilibrium it acts as a normal charging event. The rapidly charging amplitudes depend on many factors, such as the switch-on time of the solar arrays, the pattern of switch-on, etc., which play key roles, and so that the floating potential data exhibit a spread to a certain extent. The maximum potential decreases with electron density increasing, which is in good agreement with observations.
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