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在自然界中地层会呈现出各向异性特征,各向异性介质的研究有助于资料解释和认识地球动力学的过程,但当前数据处理中多数使用各向同性理论解释各向异性构造,因而对电磁资料解释造成了一定的偏差。当前,时间域航空电磁法关于各向异性的解释仍局限于一维情况,且相应的三维数值模拟也正处于研究中,因此本文针对任意各向异性介质中三维时间域航空电磁法进行正演模拟。将各向同性介质的电导率经过坐标旋转后,得到任意各向异性介质的电导率张量,将其引入到麦克斯韦方程组中,采用矢量有限元法的规则网格对求解区域进行剖分,利用直接求解器对总体合成的线性方程组进行求解。通过与解析解对比,验证了算法的精确性和可行性;同时与各向同性情况进行对比,通过响应的分布特征及幅值变化分析任意各向异性对三维时间域航空电磁响应的影响,得出在不同情况下各向异性对时间域航空电磁响应的影响情况存在较大差异。
In nature, the strata exhibit anisotropy. The study of anisotropic media is helpful for the data interpretation and understanding of the process of geodynamics. However, most of current data processing uses isotropic theory to explain the anisotropic structure. Therefore, Electromagnetic data interpretation caused a certain deviation. At present, the explanation of the anisotropy of the time domain electromagnetic electromagnetic method is still limited to the one-dimensional case, and the corresponding three-dimensional numerical simulation is under study. Therefore, in this paper, aiming at the three-dimensional time domain aeromagnetic method in any anisotropic medium simulation. The conductivity tensor of anisotropic medium is obtained by rotating the electrical conductivity of isotropic medium through coordinate transformation. The conductivity tensor of arbitrary isotropic medium is introduced into Maxwell’s equations. The regular grid of vector finite element method is used to divide the solution area, Solve the general linear equations by using the direct solver. By comparing with the analytical solution, the accuracy and feasibility of the algorithm are verified. At the same time, it is compared with the isotropic condition, and the influence of arbitrary anisotropy on the aeronautical electromagnetic response in three-dimensional time domain is analyzed through the distribution of the response and the amplitude variation There are big differences in the influence of anisotropy on the electromagnetic response in time domain in different situations.