Forward modeling for “earth-ionosphere” mode electromagnetic field

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• 作者：Di-quan Li 李帝铨 ; Wei Xie 谢维 ; Qing-yun Di 底青云…
• 关键词：Key wordsearth ; ionosphere mode ; large power ; large offset ; electromagnetic field ; forward modeling
• 刊名：Journal of Central South University
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：23
• 期：9
• 页码：2305-2313
• 全文大小：2,340 KB
• 刊物类别：Engineering
• 刊物主题：Engineering, general
  Metallic Materials
  Chinese Library of Science
  
• 出版者：Central South University, co-published with Springer
• ISSN：2227-5223
• 卷排序：23

文摘

A fixed artificial source (greater than 200 kW) was used and the source location was selected at a high resistivity region to ensure high emission efficiency. Some publications used the “earth-ionosphere" mode in modeling the electromagnetic (EM) fields with the offset up to a thousand kilometer, and such EM fields still have a signal/noise ratio of 10–20 dB. This means that a new EM method with fixed source is feasible, but in their calculation, the displacement in air was neglected. In this work, some three-layer modeling results were presented to illustrate the basic EM fields’ characteristics in the near, far and waveguide areas under “earth-ionosphere” mode, and a standard is given to distinguish the boundary of near, far and waveguide areas. Due to the influence of the ionosphere and displacement current in the air, the “earth-ionosphere” mode EM fields have an extra waveguide zone, where the fields’ behavior is very different from that of the far field zone.