摘要
大功率人工源极低频电磁波(Control Source of Extremely Low Frequency method,CSELF)技术中,辐射天线由布设在高大地电阻率区的接地长导线源构成,通过接地点向大地注入数百安培的强电流.目前有关强电流在大地中的流动特性和分布规律,尚未完全弄清楚.本文提出一个新思路,将CSELF发射天线分解为两部分:交变的接地长导线源和接地处的交流点电流源,二者响应的叠加构成总场.本文重点讨论了均匀空间下交流点电流源的求解,对比研究了交流点电流源响应、直流点电流源响应之间的差异.结果表明,在小范围内(场源距几十、几百米以内),均匀空间下交流点电流源场和直流源场差别较小,可相互近似,但在大范围内,交流点电流场比直流场的衰减要快得多.由于CSELF辐射天线跨度上百公里,场源距很大,其电流分布规律遵循交变场规则,不能近似为直流场.
In Control Source of Extremely Low Frequency （CSELF） method, an antenna is composed of very long grounding electrical line which is distributed along high resistivity route. Strong currents usually more than one hundred Amps are injected into the earth through the grounding ends, of which the flow and distribution characteristics are still not very clear yet. A new idea is put forward in this paper. The antenna is separated into two parts. One part is a long electrical line source with alternating current （AC）. The other is an AC point source. The total field can be obtained by the vector sum of the responses excited by both sources. Here the solution of problem of AC point source in a uniform space is discussed in detail, The responses excited by an AC point source and a DC point source are compared carefully. The results show that there is little difference between an AC point source and a DC point source in the uniform space within a small scale region （the distance of site to source is about tens or hundreds meters）. An AC point source can be approximated by a DC point source; but in a large region, the attenuation of the field excited by an AC point source is much faster than that of a DC point source. Because the antenna of CSELF is rather long, where the distance of site to source is very large in general, thus the distribution of current in the earth satisfies the AC law, and could not be approximated by a DC point source.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第8期2158-2164,共7页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(40674036)
中央级公益性科研院所基本科研业务专项(DF-IGCEA-0607-1-6)
地震行业科研专项经费(200808010)资助
关键词
CSELF
交流点电流源
均匀空间
电流分布
CSELF, Alternating point source, Uniform space, Current distribution
