Design, Manufacturing and Tests of an All-HTS 20 T Magnet

High field magnets are required for fusion, biochemical and other scientific applications. Utilization of second generation high temperature superconductors (2G HTS) in such magnets is beneficial for achieving record magnetic fields. 2G HTS-based magnet was successfully designed, manufactured and tested. The magnet consists of two coaxial coils: a partially insulated 40 mm cold bore layer-wound inner section and an outer section with eight double pancakes (100 mm cold bore). The special high-field YBCO conductors were developed and produced: 12 mm mechanically reinforced tape for double pancakes and 4 mm two-tape stack for layer windings. Both HTS conductors are partially or fully insulated by UV cure urethane varnish. The double pancake pack were additionally reinforced by Hastelloy wrapping and aluminum casing. The superconducting magnet with HTS bus-bars and HTS current leads was installed into a helium cryostat. Two cryocoolers were used, one for helium re-condensation and another for current leads cooling. Inner and outer sections of the magnet operated separately by different power sources. During the tests was achieved magnetic field 20.1 T.