A New Coupled Electrodynamic T – A and Thermal Model for the Critical Current Characterization of High-Temperature Superconducting Tapes and Cables

Abstract

Future collider accelerators will rely on high-temperature superconductors reaching high field up to 20 T and above. Among the existing high-temperature superconducting materials, the Rare-earth Barium Copper Oxide (ReBCO ) tapes arranged according to the Conductor-on-Round-Core (CORC ® ) concept could be a viable solution to wound accelerator magnets such as Cosine Canted Theta (CCT) magnets. Dedicated experimental characterization of the critical current to quantify the degradation due to the winding process and operating conditions should proceed in parallel to the development of numerical models capable to reproduce and, in perspective, predict the cable performance. This paper presents the development of a new multi-physics model for a CORC ® wound with ReBCO tapes together with its validation. The T − A formulation has been used leveraging the high aspect ratio of tapes, suitably coupled with a conduction thermal model which for the first time properly accounts for the cable convective cooling. The model developed in this work can accurately simulate the thermal, electric and magnetic behaviors and the current sharing among tapes by using a set of self-consistent boundary conditions adopted for the first time in this kind of simulations. The model is verified and benchmarked against other well-established formulations on a set of test cases. The comparison of the computed V − I characteristic of the straight cable to available experimental data shows that the main physics features of the cable are well captured by the model, including performance degradation due to cable tapering at the terminations.INDEX TERMS Numerical models, CORC ® cables, critical current, multiphysics model, high-temperature superconductors,hybrid formulation.