Successful Development of High-Temperature Superconducting Central Solenoid Coil for Fusion Reactors

China’s Superconducting Tokamak research team has successfully developed and fully tested a high-temperature superconducting (HTS) central solenoid coil for fusion reactors, with all key performance indicators reaching internationally advanced levels and full domestic localization achieved in materials, structural design and manufacturing processes.

Full-parameter testing confirms the coil delivers a stable operating current of 60 kA, a stored energy of 6.03 MJ, a maximum magnetic field ramp rate of 5.1 T/s, and an ultra-low joint resistance of 0.87 nΩ, outperforming the designed technical thresholds. As a core component of Tokamak devices, the coil supports device startup, plasma current excitation and real-time plasma confinement regulation, and is capable of long-term stable operation under extreme conditions of high current, heavy mechanical stress and alternating pulsed magnetic fields.

Facing extreme technical challenges, the team adopted an innovative hybrid high-low temperature magnet structure with stress-dispersion support, overcoming over ten key technical bottlenecks including high-stability magnet design, large-current HTS conductor fabrication, precision conductor forming, ultra-low-resistance joint manufacturing and magnet quench protection.

The project completed key phased milestones from 2023 to 2026, including third-party verification at the SULTAN facility in Switzerland and the development of hundred-meter-level HTS cable-in-conduit conductors. The breakthrough establishes complete independent core technologies and intellectual property rights, laying a solid foundation for the long-term engineering application of high-field HTS magnets in future fusion reactors. 

Test site