摘要
在SLF/ELF频段,离子的磁回旋频率接近甚至高于电波频率,其对电波传播的影响不能忽略。深入分析了SLF/ELF电磁波在电离层中传播时,离子对折射指数、极化因子等参数的影响。研究结果表明:在离地高度大于200 km的高电离层,由于电子与离子的碰撞频率远小于磁回旋频率和电波的频率,离子对电波传播的影响很大。在离地高度70 km左右的低电离层,电子与离子的碰撞频率远大于磁回旋频率,离子对电波传播的影响就可忽略。因此,就SLF/ELF对电离层的反射而言,可不计离子的作用;但对于透射传播,应该考虑离子的作用。
The influence of ions on wave propagation must be considered in SLF/ ELF because the gyro-frequency for ion is nearer or higher than wave-frequency. The effect of ions on refractive index and polarisation is analyzed in this paper. The result show that the effect of electro- and ionic collisions on wave-propagation can be neglected for that the collision-frequency is comparable with, or much less than gyro-frequency and wave-frequency in higher region of the ionosphere having above 140 km height away from the earth＇s surface, here the influence of ions on wavepropagation is obvious. In lower region of the ionosphere the effect of collisions on wave propagation can not be neglected because electro- and ionic collision-frequency is much more than gyro-frequency, here the influence of ion on wave propagation is small relatively.
出处
《电波科学学报》
EI
CSCD
北大核心
2008年第6期1128-1132,1193,共6页
Chinese Journal of Radio Science
基金
国家科技支撑项目(2008BAC35B05)
关键词
电离层
电子
离子
碰撞
准纵近似
ionosphere
electron
ion
collision
quasi-longitudinal approximation
