空间多能电子辐照聚合物充电过程的稳态特性

空间同步轨道上多能电子辐照聚合物的充电过程及其稳态特性是研究和抑制通信卫星静电放电的基础.在同步电子散射-输运微观模型的基础上,采用具有10—400 keV积分能谱分布的多能电子辐照聚酰亚胺样品,进行了多能电子辐照聚酰亚胺充电过程的数值模拟,获得了空间电荷密度、空间电位、空间电场分布和聚合物样品参数条件下的表面电位和最大场强.结果表明,多能电子与样品发生散射作用并沉积在样品内形成具有高密度的电荷区域分布,同时在迁移和扩散的作用下输运至样品底部形成样品电流;充电达到稳态、电子迁移率较小时(小于10-10cm2·V-1·s-1),表面电位绝对值和充电强度随电子迁移率的降低明显加强,捕获密度较大时(大于1014cm-3),表面电位绝对值和充电强度随捕获密度的增大明显加强;聚合物样品厚度对表面电位和充电强度的影响大于电子迁移率、捕获密度和相对介电常数的影响.研究结果对于揭示空间多能电子辐照聚合物的充电现象及微观机理、提高航天器故障机理研究水平具有重要科学意义和价值.

Steadystate charging characteristics of polymer irradiated by multi-energetic electrons

Charging characteristics of polymer irradiated by multi-energetic electrons is a basis to study and prevent electrostatic discharge in space radiation environment. The polymer irradiated by multi-energetic electrons is modeled and simulated. The space charge distribution, surface potential, space potential, surface potential and maximum field strength under the condition of sample parameters are obtained. The results show that because of electron drift and diffusion, electrons can transit through the electron scattering region, forming negative space charges. Some electrons can flow to the substrate of polymer. In the equilibrium state, the surface potential of the film negatively charged decreases with film thickness and trap density increasing, and it increases with electron mobility and relative permittivity increasing. The maximum field strength increases with film thickness and trap density increasing, and it decreases with electron mobility and relative permittivity increasing. The high-energy electrons section of multi-energetic electrons will shorten the equilibrium of charging process.
Keywords： space radiation polyimide multi-energetic electrons steady-state characteristics