卫星外露电缆束介质结构深层充电仿真分析

受到空间高能带电粒子的作用,航天器蒙皮外侧电缆束的绝缘介质会产生深层充电效应。基于介质的电流连续性方程,并利用Geant4粒子输运模拟和辐射诱导电导率公式分析了介质深层充电的物理过程。在地球同步轨道(GEO)恶劣电子环境下,对外露电缆束介质结构深层充电进行三维仿真分析。结果表明:深层充电导致介质结构带20 V以内负电位,电位和电场强度峰值分别出现在电缆束外圈电缆介质层的外侧与内侧;对于导线介质层厚度为0.19 mm的情况,各介质层间是否紧密邻接和电缆束包含电缆根数多少对充电峰值结果影响不大;捆缚电缆的条状介质块是发生放电的危险区域,介质块厚度为0.8 mm时,充电电位在-103 V量级,电场强度可达到4×106 V·m-1,且电场强度与电位随介质块厚度增加而显著增大。

Simulation of deep dielectric charging on satellite's exposed electric cable bundle

The energetic charged particles in space can lead to deep dielectric charging on exposed electric cable bundles outside the satellite skin. Based on the principle of the current conservation, the process of deep dielectric charging is analyzed using the particle transport simulation software Geant4 and the radiation induced conductivity formula. In the GEO severe electron flux environment, the three-dimensional simulation is carried out for the deep dielectric charging of exposed electric cable bundles. It is shown that the balanced potential is negative, the peaks of the potential and the electric strength appear on the external and internal surfaces of the outermost cables in a bundle, respectively. Little effect on the internal charging results is shown whether the dielectric layers of cables in a bundle are connected to each other or not and how many cables are in the bundle. It is the dielectric bar binding the cables that involves high discharging risks. When this dielectric bar''s thickness is 0.8 mm, the charging potential and the electric strength are about -10³ V and 4×10⁶ V·m^-1, respectively. What''s more, the potential and the electric strength will increase considerably as this thickness is enlarged.