The Finite-Difference Time-domain Numerical Simulation Of Three-Dimensional Quasi-stationary Transient Electromagnetic Field Response In The Conductive Media

In tradition,the study of the electromagnetic theory focus on the propagation of the transient electromagnetic field,which propagates in sinusoidal form with time.At present,the theory and experimentation of the transient electromagnetic field have got great achievement.In recent years,the research of the propagation pattern of the electromagnetic pulse has been given more attention.The research of the Quasi-stationary transient electromagnetic field is an important research area in geophysical applications.Three-dimensional numerical simulation of transient field is an important method to study the propagation in conductive medium.Three-dimensional finite difference time domain solution has been realized in this paper.Maxwell equations curl equation of the magnetic field does not constitute an explicit time iterative recursive formula in the Quasi-stationary fields,so the virtual displacement current has been introduced.The value of the virtual displacement current must ensure the stability and the dominant of the current conduction.However,the characteristic of the Quasi-stationary fields enable the region to solve the top of a compression to the ground grid, the greatly reduced capacity of computer memory requirements and speed up the computing speed.The method of the excitation source added has been improved based on the work of predecessors in this paper.The revised liner step pulse directly added the FDTD formula and iteratively calculation the electric and magnetic fields.Using this FDTD method simulates the different resistivity in the homogeneous half-space,which generates the electromotive force compared with the results of analytical solution by loop source.The error has been detected to satisfy the requirements of practical engineering,the source of this approach and FDTD procedure is correct.Furthermore,The three-dimensional FDTD method compared with the magnetic dipole source in the homogeneous half-space model,with the goal of the homogeneous half-space model by the loop source,and the low resistance of the coating target in the homogeneous half-space model.The correctness of this FDTD algorithm has been further verified.Excitation pulse will be injected into the FDTD algorithm approach,which can simulate the more complex model,the greater adaptability for the different transient device...