有限元方法研究精细地-电离层波导VLF波传播特性  

Research on propagation characteristics of VLF waves in the fine earth-ionosphere waveguide using the Finite Element Method

作　　者：刘兵 王茂琰[1] 张世田[2,3] 徐彤[2] 李海龙[1] 吴健[2] LIU Bing;WANG MaoYan;ZHANG ShiTian;XU Tong;LI HaiLong;WU Jian(School of Physics,University of Electronic Science and Technology of China,Chengdu 610054,China;National Key Laboratory of Electromagnetic Environment,China Research Institute of Radiowave Propagation,Qingdao 266107,China;School of Physics and Optoelectronic Engineering,Xidian University,Xi'an 710126,China)

机构地区：[1]电子科技大学物理学院,成都610054 [2]中国电波传播研究所电波环境特性及模化技术重点实验室,青岛266107 [3]西安电子科技大学物理与光学工程学院,西安710126

出　　处：《地球物理学报》2023年第5期1820-1828,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(62271113,61971351);电波环境特性及模化技术重点实验室开放基金(202102010,6142403,11905026)资助。

摘　　要：基于频域有限元方法仿真了精细地-电离层波导结构甚低频(VLF,Very Low Frequency)电磁波幅度和相位传播特性.首先给出了如何确定VLF波发射点和接收点传播路径所在大圆的方法,接着分析了获取波导结构中不同阶波导模式传播系数的耦合模理论,数值讨论了不同阶波导模式的衰减率和相对相速度随模式数和工作频率的变化关系,给出了波导不同结构参数对一阶模衰减率和相对相速度的影响.与文献结果对比验证了本文有限元方法模拟VLF波传播的正确性和高效性.最后利用实验和数值仿真结果,通过对电子密度国际电离层参考模型进行修正,讨论了澳大利亚—青岛台VLF波幅度和相位日变化的规律.本文工作为研究地-电离层波导结构VLF波电磁特性以及提高陆基超远程甚低频导航系统的精度,提供了新的思路和方法.The amplitude and phase propagation characteristics of very low frequency(VLF)electromagnetic waves in the fine earth-ionosphere waveguide structure are simulated based on the frequency-domain finite element method in this paper.First,the method about how to obtain the propagation path for the big circle containing the VLF transmitter and receiver locations is given.The coupling mode theory on the waveguide structure is analyzed to achieve propagation coefficients of various order waveguide modes.The relations between the attenuation rate and relative phase velocity of different order waveguide modes and the mode number and working frequency are numerically discussed.The effects of structure parameters for the waveguide on the attenuation rate and relative phase velocity of the first order mode are given.By comparing with results in the reference,the validity and high efficiency of VLF wave propagation simulated by using the finite element method in this paper is confirmed.Finally,electric densities from the International Reference Ionosphere model are revised by employing the experimental and numerical simulation results.The daily variation rule for the amplitude and phase of the VLF waves from Australia to Qingdao is discussed.This work provides a new way and method for the study of electromagnetic characteristics of VLF waves in the Earth-ionospheric waveguide structure and the improvement of the precision for the land-based VLF ultra-long-range navigation.

关 键 词：甚低频 地-电离层波导 相位 模式耦合理论 

分 类 号：P352[天文地球—空间物理学]