Design of High Field HTS Coils for Magnetic Mirror

This paper outlines the preliminary design of an experimental compact (<2 tons), high-field (similar to 20 T on tape, similar to 17 T at center bore), and conduction-cooled HTS REBCO magnet. An identical pair of these magnets will be manufactured for a magnetic mirror axial fusion device. The magnet consists of eight single pancakes in series, each of which is an interchangeable, dry-wound, partial-insulated winding. Once charged, the magnet is operated with a constant current and will be used in the presence of other magnets. Field-induced mechanical stresses in the winding pack are managed using a novel technique of 'partitions' keyed into structural plates. The system is conduction-cooled by cryocoolers to operate at 20 K. The winding pack is mechanically supported and thermally isolated in the cryostat by high-strength, low-thermal conductivity brackets designed to sustain over 60 tons of axial loading during peak device operating conditions.