An Integro-Differential Time-Domain Scheme for Electromagnetic Field Modeling in HTS Materials

In this article, we developed a 3-D integro-differential model in the time domain for the electromagnetic field computation in high-temperature superconductive (HTS) composite materials which are characterized by a nonlinear anisotropic electrical conductivity and multiscale dimensions. The model is formulated in terms of the electric vector potential and discretized by using the finite-difference method coupled to a collocation method for the integral part. Only the active parts of the system are discretized. A relaxation method is applied to improve the convergence of the solution and to reduce the computation time. In the aim validation, a numerical example is considered where the numerical evaluation of ac losses in a Bi-Sr-Ca-Cu-O type HTS tape is compared to an analytical calculation using measured parameters.