论文部分内容阅读
在瞬变电磁法的实际应用中,由于发射回线和发射波形的不规则性而导致其发射源成为时空展源.展源效应的忽略会造成正反演和数据解释的差错,因此开展展源效应的研究对于瞬变电磁法的实际应用具有重要的意义.对于空间展源,本文以磁偶极子的响应为基响应,应用有源空间的互易定理和第二类曲线积分,提出了一种可基于发射回线数值坐标求取任意形状发射回线响应的计算方法.同时对于时间展源,以阶跃波形的响应为基响应,对阶跃响应的特性进行了分析,提出了一种对发射信号进行非均匀采样的高效时间域计算方法,解决了对数采样的基响应与高密度采样的发射波形之间进行常规卷积时所面临的时间与精度之间的矛盾.通过对层状大地上展源响应的模拟仿真和对比验证显示了本文所提出方法的正确性.最后本文考察了几种常见时空展源在常规近似前后响应的差别,并给出了相关结论.
In the practical application of TEM, the emission sources become the source of space-time due to the irregularity of the transmitted return line and the transmitted waveform. The neglect of the source effect causes the errors of forward inversion and data interpretation. Therefore, The study of source effect is of great significance to the practical application of transient electromagnetic method.In this paper, based on the response of magnetic dipole, the paper presents the reciprocal theorem of active space and the integral of the second kind of curve A new method to calculate the echo response of arbitrary shape based on the numerical coordinates of transmitting return line is proposed. At the same time, the response of the time waveform source is based on the response of the step waveform, and the characteristics of the step response are analyzed. A highly efficient time domain calculation method for nonuniformly transmitting a transmitted signal solves the conflict between time and accuracy faced by a conventional convolution between the base response of logarithmic sampling and the emission waveform of a high density sample. Simulations and comparative verification of the response to the expo source on the layered earth show the correctness of the method proposed in this paper.Finally, we examine several common spatiotemporal sources before and after the conventional approximation Differences, and gives the relevant conclusions.