Development and construction of magnet system for world’s first full high temperature superconducting tokamak

In June 2024, the world’s first full high temperature superconducting (HTS) tokamak has successfully achieved its first plasma operation in Shanghai, China [1] . This tokamak device, HH70, is designed by Energy Singularity Fusion Power Technology (Shanghai) Ltd. (ES Company) in Shanghai, China. The conceptual and engineering design of HH70 was initiated in June 2022, whose major radius (R 0 ) and minor radius (a) are 0.7–0.75 m and 0.25–0.31 m, respectively. Its toroidal magnetic field B 0 at R 0 = 0.7 m is 0.6 T, the total inductance of the toroidal field (TF) magnet are 6.48 H. Over the past two years, ES company has achieved the first milestone: successfully design, construct and operate an HTS tokamak, and has amassed experience and know-how about such a first-of-its-kind HTS device. The HH70 tokamak’s magnet system consists of three types of coils: central solenoid (CS) coil, poloidal field (PF) coil, and toroidal field (TF) coil, in which all of the coils are fabricated by HTS conductors. Hence, the HH70 is currently the first tokamak in the world to be fully integrated with HTS coils, marking a groundbreaking advancement in fusion technology.