摘要
针对水平层状介质点电流源格林函数,提出了一种快速计算技术。该方法利用点电流源层状介质格林函数谱为单调实函数的特点,采用多指数级数近似格林函数谱,进而借助Somerfeld-Lipschtz积分实现格林函数的闭式计算。计算过程中,格林函数谱以等对数间隔抽样,近似多指数级数的指数常数保持固定并被等对数间隔抽样,近似过程只是指数级数系数谱的计算过程。计算结果表明,采用如下参数能实现点电流源格林函数高精度闭式计算:(1)λmin=10-6,λmax=10,采样点N=128,λ对数抽样;(2)T2min=10-7,T2max=103,T2对数抽样,抽样个数M=64;(3)最优正则化参数α2=10-5,采用最简单模型对解进行约束。
A novel method is developed to compute the Green’s function of a current point source buried in electrical conductive layered earths.In this method,the kernel function of Green’s function is firstly approximated by multi-exponential series with the fact that the function is real and mono-decay or mono-increase,and then with the help of Somerfeld-Lipschtz integration,the Green’s function can be expressed in a closed form of the summation of a finite series.Numerical results show that with the following optimized parameters,one can get a highly accurate computation of Green’s function：（1）λmin=10-6,λmax=10,with number of samples N=128,and λ sampled in logarithmic mode;（2） T2min=10-7,T2max=103,T2 is sampled in logarithmic mode with 64 samples;（3） the most optimized regularization parameter α2 could be 10-5,and the simplest model is the preferred solution constraint
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2011年第1期258-264,共7页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(40874050)
国家'863'计划项目(2006AA06Z109)
关键词
电磁法
格林函数
层状介质
点电流源
多指数逼近
Prony级数
electromagnetic method； Green’s function； layered earth； current point source； multi-exponential approximation； Prony series
