DEMETER卫星监测的极低频和超低频电磁场数据分析

摘要

分析了DEMETER卫星上测量的极低频(ELF,3-30 Hz)和超低频(SLF,30-300 Hz)水平磁场.其统计变化规律与地面上实测的此频段大气噪声变化规律一致,并且数值差异也符合电波传播规律,说明卫星上监测的电磁场来源于地面.同时对DEMETER卫星上测量的ELF和SLF归一化波阻抗进行了深入地分析,由电子密度与离子密度计算出的归一化波阻抗与由实测电磁场计算出的归一化波阻抗均有差异.现有观测资料并不完全“自洽”,尚有问题需深入研究.%The statistic variation of horizontal magnetic field measured by the DEMETER satellite in the ELF (3-30 Hz) and SLF (30-300 Hz) range is compared with the atmosphere noise measured on ground.The difference between DEMETER and ground observations accords with the law of radiowave propagation.Therefore,it indicates that the electromagnetic field measured by the DEMETER satellite originates from the earth ground.Then,the normalized wave impendence of ELF/SLF measured by the DEMETER satellite is profoundly analyzed.The normalized wave impendence calculated from the electron density and ion density is quite different from the value calculated from electromagnetic field measurement.The present data is not self-consistent,and some problems need to be further studied.