极轨航天器尾区带电效应研究

STUDY OF WAKE CHARGING OF POLAR SPACECRAFT

当航天器运行在低能、高密度的低轨等离子体环境中时,由于航天器轨道速度大于离子的热速度而远小于电子的热速度,因此电子可较容易地进入航天器尾部并沉积到表面材料上,从而形成一负电位势垒产生所谓的"尾区效应"。特别是在地球极区的背景等离子体环境中,由于高能极光电子的注入,大倾角极轨航天器尾区介质材料将会发生严重的充电过程。通过对拟合极光电子的微分通量谱分布分析,计算了极光电子收集电流和背景等离子体中离子的收集电流。

Since the velocity of the spacecraft in cold and dense plasma is larger than local ion velocity but moresmaller than electronic velocity,the electrons could more easily move into the wake area and consequently form a highnegative potential barrier,which produces wake charging effect. Especially in Polar Earth Orbit（PEO）,where exists energeticauroral electrons injection,the dielectric materials in the wake area can be charged to high negative potential. In thispaper the physical mechanism of wake charging effect were analyzed,and the physical model was established by using ofdouble Maxwellian distribution of energetic aurora electrons and accounted the effect of the background plasma and secondaryelectrons.