摘要
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.
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.
作者
LI Di-quan
李帝铨;谢维;底青云;王妙月(Key Laboratory of Metallogenic Prediction of Nonferrous Metals of Ministry of Education （Central South University）, Changsha 410083, China School of Geosciences and Info-Physics, Central South University, Changsha 410083, China Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China)
基金
Projects(41204054,41541036,41604111)supported by the National Natural Science Foundation of China
作者简介
Corresponding author： XIE Wei, PhD; Tel： ＋86-731-88877075; E-mail： xw76676372@126.com
