Thin Shell Model of a Coated Conductor With a Ferromagnetic Substrate

Coated conductors with magnetic substrates are thin multilayer structures; their high aspect ratio and nonlinear material properties present significant difficulties for numerical simulation. Using the high width-to-thickness ratio of coated conductors we derive an integral formulation for a model based on an infinitely thin approximation for the superconducting layer and a quasistatic thin shell approximation for the magnetic substrate. The proposed model describes electromagnetic response of a coated conductor with a magnetic substrate and is much simpler than the existing models. A single dimensionless parameter characterizes the substrate having a finite magnetic permeability and a finite thickness. An accurate and efficient Chebyshev spectral method is derived for numerical solution. The influence of a magnetic substrate on the superconducting current and ac losses is investigated. In the limiting cases our model solution tends to the known analytical solutions.