This paper studies the effect of the initial values of different potentials on the surface potential attenuation of spacecraft dielectric materials.The method is as follows:charge the PI and PTFE dielectric materials to different potential values using spacecraft simulation equipment,then close the electron gun and measure the attenuation curve of the surface potential of the dielectric material with a potentiometer,and theoretically analyze the cross-over phenomenon.The result shows that,the higher the initial potential value of the dielectric material,the faster the surface potential decay rate,and the potential decay effi-ciency increases with the initial potential value in a certain period of time,under the same vacuum condition,for the two sets of attenuation curves with the same sum of initial potentials,the closer the initial potential values are,the more likely the cross-over phenomenon will occur;the time at which the cross-over occurs is related to the mobility of the electrons,under the same initial potentials,the longer the mobility,the shorter the time before the cross-over occur and the faster the potential attenuates.It is concluded that the values of the charge potential on the surface of the spacecraft affects the attenuation efficiency and the decay rate of the potential.%为了研究航天器介质材料表面不同电位初始值对表面电位衰减特性的影响.利用航天器带电地面模拟实验设备对聚酰亚胺和聚四氟乙烯介质材料充电到不同电位值,然后关闭电子枪,用电位计测量介质材料表面电位的衰减曲线,并从理论上对cross-over现象进行分析.介质材料初始电位值越大,则表面电位衰减速度越快,且在一定的时间段内电位衰减效率随初始电位值的增大而变大;在相同的真空度条件下,对于初始电位值之和相等的两组衰减曲线,初始电位值之间差值较小的一组衰减曲线更容易出现cross-over现象;出现cross-over现象的时间和电子的迁移率相关,对于相同的两个初始电位,迁移率越大的材料则出现cross-over现象的时间越短,电位衰减会更快.航天器介质材料表面充电电位越大则衰减速度越快,在一定时间的衰减效率越高.
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