The internal charging effect may lead to electrostatic discharges (ESDs) for Geostationary Earth Orbit (GEO) and Middle Earth Orbit (MEO) satellites. This is due to the high-energy electrons that deposit in the dielectrics of satellites. The properties of the dielectrics such as permittivity and dark conductivity dominate this effect. This may contribute to the ESD risk of long-lifetime satellites if these properties change with the increase of electron dose. Two general materials, Polyimide (PI) and FR4 Epoxy Glass Cloth (FR4), were chosen as samples to study by experiments with different doses. The results show that the permittivity of PI and FR4 decreased as the dose increased while the dark conductivity increased. Numerical simulation evaluates the electron dose and the ESD risk of dielectrics under the electron environment of a specific MEO electron spectrum. The results show that the decrease of permittivity and the increase of dark conductivity will shorten the time constant of internal charging. The quicker build-up of electric field will increase the ESD risk if it exceeds the breakdown threshold.

中文翻译：

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聚酰亚胺和FR4介电常数和暗电导率随电子剂量变化的实验研究


内部充电效应可能会导致对地静止地球轨道 (GEO) 和中地轨道 (MEO) 卫星的静电放电 (ESD)。这是由于卫星电介质中沉积了高能电子。介电常数和暗电导率等电介质的特性决定了这种效应。如果这些特性随着电子剂量的增加而变化，这可能会导致长寿命卫星的 ESD 风险。选择聚酰亚胺（PI）和FR4环氧玻璃布（FR4）两种通用材料作为样品，进行不同剂量的实验研究。结果表明，随着剂量的增加，PI和FR4的介电常数降低，而暗电导率增加。数值模拟评估了特定MEO电子谱的电子环境下电介质的电子剂量和ESD风险。结果表明，介电常数的降低和暗电导率的增加会缩短内部充电的时间常数。如果电场建立得更快，超过击穿阈值，就会增加 ESD 风险。