Recently, the HH70 high-temperature superconducting tokamak has successfully carried out operation experiments that exceeded its standard design conditions. In this experiment, the toroidal magnetic field (B0) of HH70 reached 1.02 Tesla (3.1 Tesla on HTS tape), with the performance of the device significantly improved.

Fig. Toroidal magnetic field vs. TF current

The HH70 is the world’s first fully high-temperature superconducting tokamak developed and constructed by Energy Singularity. Under the standard design conditions, the toroidal magnetic field (B0) of this device is 0.6 Tesla (2.5 Tesla on HTS tape). It is worth mentioning that, to ensure the engineering reliability of the device, we have taken into account a considerable engineering margin in the design. When the magnet system of the HH70 operates under the standard design conditions, the current-carrying ratio (the ratio of the actual operating current to the critical current) of its high-temperature superconducting conductors is around 30%. In June of this year, the HH70 successfully obtained the first plasma. Subsequently, we optimized the cryogenic system of the device in order to achieve a lower operating temperature for the magnets and thus obtain a stronger confinement magnetic field. In this experiment, the operating temperature of the magnet system was further reduced from 20K under the standard design conditions to 9K, and the current-carrying ratio was increased from 30% to 50%, thus successfully achieving a toroidal magnetic field (B0) exceeding 1 Tesla.

This HH70 experiment has further verified the engineering reliability and robustness of fully high-temperature superconducting tokamak, and laid the foundation for HH70  to achieve a steady-state plasma with higher-performance and longer-pulse in 2025.

Finally, we wish everyone a Happy New Year!