电子辐照下聚合物介质内部放电模型研究

Macroscopic model of internal discharging in polymer under electron beam irradiation

空间电子辐照环境中,聚合物介质充放电现象是威胁航天器安全的重要因素.传统航天器介质充放电模型仅能分析材料充电过程,缺乏对放电前后介质电位残余情况与放电脉冲强弱的评估.本文通过引入介质放电电导率,在数值积分充电模型基础上建立同时描述航天器介质内部充电和放电过程的新模型,并将模型计算结果与实验数据进行比较,验证了所构建的模型.模型分析结果表明,聚合物介质放电残余电位与放电电流脉冲宽度随着样品电阻率的增加而增大,放电电流强度随着临界电场强度和充电时间的增加而增强,其增幅随着辐照电子束流强度的增加而增大.

Internal charging effect and discharging effect in a dielectric material are one of the key factors threatening the spacecraft safety. Most of the spacecraft charging models could calculate only the voltage variation and electric field distribution in the spacecraft internal charging process, without estimating the consequence of discharging, such as the magnitude of voltage drop and discharging current. In this article, we present a combined model which could calculate both the charging effect and the discharging effect on polymer. The model is verified by the experimental results, and it shows that the residual voltage after discharging and the pulse width of discharging current grow with the increase of polymer resistivity. The magnitude of discharging current is determined by the breakdown electrical field.