Modified FFT-based method for the calculations of the thin superconductors with transport current

The Fast Fourier Transform (FFT) method was used to simulate the magnetization problems of the thin film in a perpendicular magnetic field. There are few works on the calculations of the superconducting film with transport current using the FFT-based method. To take into account the effect of the transport current, we modify the previous method and then use it to calculate the electromagnetic behaviors of the thin film. This modified method is implemented by transforming the boundary conditions of the transport current. The numerical results are compared with the integral solution for accuracy and the T–A formulation in finite elements for efficiency. The results show that the FFT-based method is an efficient method for the calculations of the superconducting film carrying transport current. Next, we simplify the 2D film problems to the infinitely long strip situation and use the modified method to calculate the strip stack problems. The results indicate that the modified FFT-based method is also valid for the computation of the strip stack problems and efficient as the number of strips is not very large.