Polar卫星在低高度时表面正高电位的统计研究

基于Polar卫星1996-2008年的表面电压数据，研究了卫星在低轨区域出现正高电位（异常事件）与太阳活动的关系及其发生位置的磁地方时（MLT）分布.研究表明:太阳辐射与异常事件发生次数呈正相关，太阳活动越活跃，异常事件出现次数越多，但不会影响航天器表面电位；异常事件发生占比呈现明显季节性变化，在太阳活动高年，冬季和夏季次数较多，春季和秋季次数较少，在太阳活动低年，每月次数均维持在较低水平，而一个月内异常事件次数没有明显规律；在分布上南北半球表现出相似性，异常事件均不会发生在地磁纬度50°-60°区域，极区和昏侧发生次数较多，而不同的是异常事件在南半球发生得更多更集中；虽然太阳活动与航天器在低高度时表面出现正高电位的次数呈正相关，但即使在太阳活动峰年，航天器异常事件发生率也不超过10%. 

Statistical Study on the Positive High Potential of Polar Satellite at Low Altitude

Based on the surface potential data of Polar satellite from 1996 to 2008, a statistical study is presented among the positive high potential of the satellite surface at low altitudes (abnormal events), the solar activity, and the MLT distributions. The main results are as follows. Firstly, the solar radiation positively correlates with the events numbers. The more active the Sun is, the more times abnormal events occur, while the solar radiation does not affect the surface potential of the spacecraft. Secondly, the proportion of abnormal events has seasonal changings. Thirdly, in the high solar activity years, the abnormal events occur more frequently in winter and summer in comparison with spring and autumn. In the low solar activity years, the abnormal events numbers maintain low values in monthly changings, and they have no apparent rules. Fourthly, there are many similarities of abnormal events in hemisphere distributions: the abnormal events do not occur at geomagnetic latitudes between 50° and 60°, but occur more frequently in the polar regions and the dusk sides. However, the abnormal events also have differences in hemispheres distributions: the abnormal events occur more frequently in the southern hemisphere. Lastly, even in the solar maximum year, the abnormal events occurrence rate does not exceed 10%.