Development of a multi-pancake HTS magnet operated in persistent current mode based on superconducting joint of REBCO coated conductors

Abstract

Developing closed-loop magnets that operate in a persistent current mode (PCM) is crucial for achieving higher resolution and sensitivity in NMR and MRI devices. To the best of our knowledge, we report a novel closed-loop multi-pancake (MP) HTS magnet operated on PCM based on a novel jointless winding method with superconducting joints of REBCO coated conductors (CCs). The in-field characteristics of the CC and the joints were investigated to determine the operating parameters of the magnet. The steady central field of the magnet reached ∼408.4 mT at 77 K with an operating current of 16.5 A. The joint resistance was inferred from a higher excitation current of 17 A to be at least less than 2.5 × 10−10Ω. Although the Ic value of the joint was considerably lower than that of the CC at self-field, it could maintain similar comparable or even higher in-field Ic compared to the CC, which is immensely beneficial for magnet applications. This study provides some insights into the design and construction of closed-loop MP magnets operating in PCM.