1. School of Geosciences and Infophysics of Central South University, Changsha 410083, China.
2. School of Geophysics and Measurement-control Technology, East China Institute of Technology, Nanchang 330013, China.
Abstract：
We have developed a hybrid solver that combines the finite-element and integral-equation method for 3D CSEM modeling based on unstructured meshes. To avoid the source singularity, the secondary field is used in the modeling framework. The primary electromagnetic field from an electric dipole source in a layered medium is calculated based on the magnetic vector potential method. The inhomogeneities of the computational region are discretized by a vector-based finite-element mesh with boundaries at finite distance from the inhomogeneities by using the dyadic Green’s function, reducing the truncation boundary effect and the solution region. The electric and magnetic Green’s function is used in data postprocessing to reduce the numerical errors owing to inaccurate gradients because of unstructured meshes; thus, the electromagnetic field is more accurately calculated. Finally, the proposed algorithm is applied to a block and a disc model, and we assess the topography effect on the field components.
. A hybrid finite-element and integral-equation method for forward modeling of 3D controlled-source electromagnetic induction[J]. APPLIED GEOPHYSICS, 2018, 15(3-4): 536-544.
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2018, Vol. 15 
