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高能带电粒子与航天器介质材料相互作用引起的深层带电现象,一直是威胁航天器安全运行的重要因素之一.考虑入射电子在介质中的电荷沉积、能量沉积分布以及介质中的非线性暗电导和辐射诱导电导,建立了介质深层充电的单极性电荷输运物理模型.通过求解电荷连续性方程和泊松方程,可以得出不同能量(0.1—0.5MeV)电子辐射下,低密度聚乙烯(厚度为1mm)介质中的电荷输运特性.计算结果表明,不同能量的电子辐射下,介质充电达到平衡时,最大电场随入射能量的增加而减小;同一能量辐射下,最大电场随束流密度的增大而增加.入射电子能量较低时(0.3MeV),最大电场随束流密度的变化趋势基本相同.具体表现为:当束流密度大于3×10-9A/m2时,最大场强超过击穿阈值2×107V/m,发生静电放电(ESD)的可能性较大.随着入射电子能量的增加,发生静电放电(ESD)的临界束流密度增大,在能量为0.4MeV时,临界束流密度为6×10-8A/m2.当能量大于等于0.5MeV时,在束流密度为10-9—10-6A/m2的范围内,均不会发生静电放电(ESD).该物理模型对于深入研究深层充放电效应、评估航天器在空间环境下深层带电程度及防护设计具有重要的意义.
Deep charged phenomena caused by the interaction between high-energy charged particles and spacecraft dielectric materials have been one of the important threats to the safe operation of spacecraft.Considering the charge deposition in the medium, the distribution of energy deposition and the nonlinear dark conductance in the medium And radiation-induced conductance, a unipolar charge transport physical model for deep charge of the medium was established. By solving the charge continuity equation and the Poisson’s equation, it can be concluded that under the different energy (0.1-0.5 MeV) electron radiation, the low density polyethylene Thickness of 1mm). The calculated results show that under the different energy of electron radiation, the maximum electric field decreases with the increase of incident energy when the charge reaches equilibrium. Under the same energy radiation, the maximum electric field with the beam (0.3 MeV), the trend of the maximum electric field with the beam current density is basically the same, which is shown as follows: when the beam current density is more than 3 × 10 -9 A / m 2, the maximum field Strongly exceed the breakdown threshold of 2 × 107V / m, the occurrence of electrostatic discharge (ESD) is more likely.As the incident electron energy increases, the electrostatic discharge (ESD) of the critical beam density increases in the When the amount is 0.4 MeV, the critical beam density is 6 × 10 -8 A / m 2, and when the energy is 0.5 MeV or more, static electricity will not occur at a beam current density of 10-9 to 10 -6 A / m 2 Discharge (ESD) .This physical model is of great significance for the further study of deep charge-discharge effect, evaluation of the deep charged degree of spacecraft in the space environment and protection design.