Development of an intra-Layer No-Insulation (LNI) Winding Method for Quench Protection of a Layer-Wound REBCO Coil

The no-insulation (NI) technique is promising as a protection method for high-field high-temperature superconducting (HTS) magnet. However, it is not suitable for layer-wound HTS coils because it has extremely long magnetic field delay due to short circuits inside winding. To solve this problem, a research group, including the current authors, proposed a novel winding method called intra-layer no-insulation (LNI) method. In this paper, we summarize the series of our studies on NI layer-wound coils and LNI coils as well as discuss issues affecting high-field magnet applications.