China Completes Testing of World's Largest Fusion Magnet — 582-Tonne Toroidal Field Coil for BEST Tokamak

The Institute of Plasma Physics (ASIPP), Chinese Academy of Sciences, completed full-condition testing on June 27, 2026 of a 582-tonne toroidal field superconducting magnet at its CRAFT (Comprehensive Research Facility for Fusion Technology) campus in Hefei, Anhui Province — the largest magnet ever built for a fusion reactor. Measuring 21m long, 12m wide and 3.3m high, the D-shaped coil has 1.3 times the volume and roughly three times the stored energy of the equivalent toroidal field coil built for ITER. It is destined for BEST (Burning Plasma Experimental Superconducting Tokamak), China's next-generation device under construction in Hefei, targeting first plasma later this decade. A companion high-temperature superconducting central solenoid coil also completed full-condition testing with internationally leading performance; sixteen such coils will eventually generate a 6.5-tesla field at the plasma center. Every component — from superconducting wire to structural steel — was manufactured domestically in China.