Preliminary Test of a Layer-Wound D-Shaped Coil Using Stacked HTS Conductor for a Miniature Toroidal Field Magnet

Abstract

High-temperature superconductors (HTS) are promising for fusion applications due to their thermal stability and high current density. We introduce stacks-in-conduit conductors (SICC) as a non-twisted alternative to traditional cable-in-conduit conductors (CICC), offering simpler fabrication while maintaining performance. Two layer-wound D-shaped coils were fabricated using stacked REBCO tapes for a miniature Toroidal Field (TF) magnet. Preliminary tests demonstrated successful current transport beyond 1100 A with typical superconducting characteristics. Two variants of the D-shaped coil were tested: one wound with substandard REBCO tapes and another with manufacturer-certified REBCO tapes. Additionally, experimental results indicate that layer-winding is an effective method for constructing HTS coils without internal joints. In the planned full operation, the D-shaped toroidal coil will be tested at 20 K and an operating current of 8 kA, with the maximum magnetic field anticipated to reach around 4.5 T.