【作者】 全荣辉；

【导师】 韩建伟；

【作者基本信息】 中国科学院研究生院（空间科学与应用研究中心） ， 空间物理学， 2009， 博士

【摘要】 空间辐射环境下,深层充放电效应是威胁航天器安全的重要因素之一。近25年(1973至1997)的统计结果表明,由介质充放电现象造成的航天器异常约占总异常现象的54.2%,其中由深层充放电效应引起的约占45.7%。因此深入研究深层充放电效应对保障航天器安全有着重要的意义。本论文通过地面模拟实验和模型分析,研究了航天器介质材料深层充放电现象。实验采用电子枪和Sr90放射源,在高真空和恒温条件下,模拟空间辐射环境对航天器常用聚合物介质辐照。通过监测样品的表面电位、放电电流和电磁脉冲信号,研究了介质深层充放电现象随电子束流强度、介质厚度和电阻率等的变化规律。论文建立辐射感应电导率模型,解释了辐射感应电导率与辐射剂量率的指数关系及指数范围,描述不同辐射剂量率及复合指数下感应电导率的变化过程。本文同时建立了深层充电模型,模型将介质的电场、电位等宏观参量与介质的载流子浓度、电荷束缚时间等微观参量相结合,对实验结果进行比较和分析,深入揭示深层充放电现象的一般规律。实验和模型计算结果表明,航天器介质材料深层充电现象随着辐照电子束流强度、介质厚度和电阻率的增加而趋于明显;介质所能达到的深层充电平衡电位随着电子束流强度和介质电阻率指数增加,其指数值小于1;介质到达深层充电平衡状态所需的时间主要由介质电阻率决定;介质深层放电电流峰值可达几十安培,电场脉冲强度可达几十伏/米,但放电脉冲宽度仅为几十纳秒至几微秒;介质深层放电高强度的电场脉冲可对试验电路造成强烈干扰。本论文的实验结果和模型可用于初步评估航天器介质材料深层充电现象,为深层充放电效应防护设计提供参考。更多还原

【Abstract】 Deep dielectric charging and discharging effect is one of the key factors threatening satellites safety in space environment. The statistic result from recent 25 years of satellites anomaly diagnosis shows that, satellite ESD caused 54.2% of all satellite accidents, in which deep charging and discharging effect attributed 45.7%.This paper studies the deep dielectric charging and discharging phenomenon with ground experiment facility. It simulates space radiation environment with an electron gun and Sr90 radiation source in vacuum. The facility radiates dielectrics at constant temperature, and monitors dielectrics surface potential, discharging current and electric field pulse. The paper also develops a radiation induced conductivity model, explaining the exponential relationship between radiation induced conductivity and dose rate. By introducing a new deep charging model, this paper compares the simulation results with experiment results and summarizes the characteristics of deep dielectric charging and discharging.The result shows that, deep dielectric charging effect becomes more serious with increasing the electron beam intensities, dielectric thickness and dielectric resistance. The deep charging equilibrium voltage grows exponentially with electron beam intensities and dielectric resistance. However, the time to reach charging equilibrium is determined by dielectric resistance. Deep dielectric discharging current can reach the amplitude of tens of ampere, and the electric field pulse amplitude could also be tens of voltage per meter. But the discharging pulse only lasts for tens of nanosecond to several microseconds. The experiment result shows that deep dielectric discharging can disturb testing circuit seriously. The experiment results and new model could be used for deep charging analysis and avoiding in spacecraft.更多还原