Conceptual design of hybrid IBS-REBCO magnet and a study on joint technology for high-field application

Abstract

The REBa2Cu3Ox (REBCO) tape, known for its exceptional mechanical properties, stands as an optimal conductor for high-field applications. Nevertheless, stress degradation attributed to the membrane and monofilament structure of REBCO tape often occurs in high-field REBCO coils. On the other hand, iron-based superconductor (IBS) tapes offer notable advantages, including multifilament structure and upper critical field above 150 T, rendering it an appealing choice for high magnetic field applications. In this context, we first propose a methodology for designing a new type of compact hybrid magnet that integrates REBCO coils with multifilament IBS coils and a water-cooled resistive magnet to generate a high magnetic field. This paper presents the preliminary design of a hybrid magnet and employs a numerical simulation model to assess the magnet's electromagnetic and mechanical configuration, the simulation results show that the stress and strain experienced by all coils is within safe limits. Furthermore, details of the fabrication and testing of the IBS-REBCO joint are also provided. We hoped that the resistance of the IBS-REBCO joint would be less than 50 nΩ, however the resistance of the joint we developed did not meet our expectations. We discuss the reasons and propose the next plan to improve the performance of the IBS-REBCO joint.