Demonstration of a Novel Insulated Two-in-Hand REBCO Magnet for High-Field Applications

This paper introduces the design and experimental demonstration of a novel insulated two-in-hand REBCO magnet for high-field applications. The insulation between turns ensures that the current flows the designed path, resulting in improved predictability during quench events with properly designed protection circuits. Conventional insulated magnets typically use Kapton tapes between turns or wrapped around the conductor, which is functional but limited by its thickness, softness, and lack of mechanical robustness. Our magnet design incorporates key innovations: the application of Pyralux insulation—a very thin Kapton layer laminated between two outer copper sheets without adhesive bonding between conductor turns—to improved mechanical properties and compactness, a four-tapes co-winding technique, which includes two REBCO tapes in parallel to enhance defect tolerance, a copper tape for protection and a Pyralux insulation tape, and the integration of intermediate rings within each single pancake coil to effectively manage mechanical stresses in large-diameter pancakes. The copper laminates in Pyralux provides a robust way to introduce a much thinner Kapton layer between conductor turns than would otherwise be possible. These innovations collectively demonstrate significant advancements in insulated magnet technology for high-field applications.