电离层-空气层-地球介质耦合下大尺度大功率可控源电磁波响应特征研究  

Study of large scale large power control source electromagnetic with “earth-ionosphere” mode

作　　者：李帝铨[1] 底青云[1] 王妙月[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学报》2010年第2期411-420,共10页Chinese Journal of Geophysics

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-121)资助

摘　　要：电离层-空气层-地球介质(我们称为"地-电离层"模式)耦合下大功率可控源电磁波的研究在国内外较少.近年来,有学者做了相关的数值模拟,但没有考虑空气中位移电流的影响.我们根据研究对象和问题建立地质模型和相应的数学模型,采用R函数法进行"地-电离层"模式水平电缆接地偶极源的电磁波场强公式推导,同时考虑电离层和空气中位移电流的影响.在验证方法可靠的前提下,进行了数值计算.探讨了"地-电离层"模式大功率可控源电磁波的响应特征.数值计算结果表明,由于电离层和空气层中位移电流的影响,"地-电离层"模式大功率可控源电磁波的特征与地球半空间可控源电磁波的特征有很大的不同,体现在前者除了有近场、远场外,还存在由于电离层影响下场强衰减变小的波导场.并随着收发距增大和频率的增高,出现了电场和磁场方向图的变化.There are only a few number of publications relate to the electromagnetic fields which including the responds of ionosphere, air and earth （called the ＂ earth-ionosphere＂ mode）. Recently, some geophysics simulated this similar mode, but the effects o5 ionosphere and displacement current in the air are not taken into account. In this study, we establish the geology model based on the ＂ earth-ionosphere＂ mode. And we apply R function method to obtain the electromagnetic fields equations for horizontal electric bipole, at the same time, the effects of ionosphere and displacement current in the air are considered. We simulate the electromagnetic fields and discuss their characters after verified the method. The results indicate that the ＂earth- ionosphere＂ mode EM fields have an extra wave-guide zone due to the influence of the ionosphere and displacement current in the air, the wave-guide field become large with the space of transmitter-receivers increasing, and the field behavior in the wave-guide zone is very different from the far field zone.

关 键 词：“地-电离层”模式 大功率 远距离 电磁波场 正演 数值模拟 

分 类 号：P631[天文地球—地质矿产勘探]