High field CORC solenoids

Low-inductance high-temperature superconductors (HTS) solenoids that generate a magnetic field as high as 40 T are required for the muon collider. No proven magnet technology exists for developing low-inductance, high field HTS solenoids for practical and reliable magnet operation. Advanced Conductor Technologies and Lawrence Berkeley National Laboratory propose to develop low-inductance high field solenoids wound from high-current HTS Conductor on Round Core (CORC®) cables. During the Phase I program, the feasibility of a 50 mm diameter bore 40 T solenoid was demonstrated. The solenoid either combined a low-temperature superconducting (LTS) outsert with several series-connected CORC® coils, or used only CORC® coils. Initial designs of 1.2 meter diameter bore 20 T low-inductance target solenoids for the muon collider were also prepared. The magnet technology required for low-inductance HTS solenoids was developed. Methods to wind three CORC® wires in parallel to match the operating current between coils and to connect CORC® coils in series over a low-resistance joint have been demonstrated. Methods to provide the CORC® conductors with sufficient mechanical support within the coils were also developed. During the Phase II program, high-level electromagnetic and mechanical designs of low-inductance 50 mm bore 40 T and 1.2 m bore 20 T solenoids based on CORC® conductors will be developed. The CORC® conductor and magnet technologies required for these magnets will be validated by testing rototype coils at high current in high background magnetic fields. The program will provide the high-energy-physics and overall scientific communities with the magnet technology needed to make practical and reliable, high-field, low-inductance solenoid magnets a reality. It will also result in a product range of smaller, low-inductance 5 – 25 T CORC® solenoids, based on the individual coils of the high-field solenoids, to serve a wider market. High-current, low-inductance HTS solenoids will enable the next generation of high-energy physics magnets operating at 40 T, magnets for scientific research and compact fusion magnets for power generation. These magnets will also benefit superconducting magnetic energy storage systems for use in the power grid and within the Department of Defense.