Integral electric current method in 3-D electromagnetic modeling for large conductivity contrast

We introduce a new approach to 3-D electromagnetic (EM) modeling for models with large conductivity contrast. It is based on the equations for integral current within the cells of the discretization grid, instead of the electric field or electric current themselves, which are used in the conventional integral-equation met hod. We obtain these integral currents by integrating the current density over each cell. The integral currents can be found accurately for the bodies with any conductivity. As a result, the method can be applied, in principle, for the models with high-conductivity contrast. At the same time, knowing the integral currents inside the anomalous domain allows us to compute the EM field components in the receivers using the standard integral representations of the Maxwell's equations. We call this technique an integral-electric-current method. The method is carefully tested by comparison with an analytical solution for a model of a sphere with large conductivity embedded in the homogenous whole space.