Analytical model of 2D electric potential and current transfer in superconducting tapes with a current flow diverter architecture

This work presents a generalization of the concept of current transfer length (CTL) between the stabilizer and the superconducting layer of high temperature superconductor (HTS) coated conductor tapes with a current flow diverter (CFD) architecture. The CFD architecture consists in a non-uniform interfacial resistance between the two layers, namely a high interfacial resistance in the middle of the tape and a low interfacial resistance on its sides. With this architecture, when the current transfers from the stabilizer to the superconductor to circumvent a normal zone or a crack, a current density component along the width of the tape appears, required for the current to circumvent the high interfacial resistance. This current component does not exist in a classical tape architecture. To describe quantitatively this current transfer, we developed a quasi-analytical formula that computes the electric potential in the stabilization layer, from which we can derive the current density components. The model is then used to determine the current transfer length (CTL) in tapes with a CFD architecture, using a generalized definition of the CTL. The model is simple and quick to run and allows deepening our understanding of the dependence of the CTL with different geometric and materials parameters, and clearly shows that the CFD architecture is very effective in increasing the CTL of HTS tapes while keeping the effective interfacial resistance to very low values. The model is quasi-analytical because it requires the numerical evaluation of a transcendental equation for determining one set of coefficients, but otherwise, it takes the form of a double summation of analytical functions (series solution). The exactness of the model has been verified by comparisons with finite element simulations.