China completes world's largest 582-tonne superconducting magnet for 'Artificial Sun'

China has marked a major milestone in its quest for commercial nuclear fusion by completing and testing a 582-ton superconducting magnet for its next-generation "Artificial Sun" programme. According to Xinhua News Agency, the 21-metre-long toroidal-field magnet is the largest of its kind ever built for a controlled fusion reactor.

Developed by the Institute of Plasma Physics (ASIPP) under the Chinese Academy of Sciences in Hefei, the giant magnet is designed to confine plasma heated to more than 100 million degrees Celsius — around six times hotter than the Sun's core. The breakthrough supports China's long-term ambition of generating electricity from controlled nuclear fusion by around 2030.

World's largest toroidal-field magnet completed

The newly built toroidal-field (TF) superconducting magnet is among the most important components of a tokamak fusion reactor. Weighing 582 metric tons and measuring 21 metres in length, it surpasses all previous fusion magnets in size.


The magnet has been developed for China's Burning Plasma Experimental Superconducting Tokamak (BEST), the country's next-generation experimental fusion reactor. Engineers recently completed its construction, factory acceptance and full-parameter testing in Hefei, marking a significant engineering achievement for China's fusion programme. Unlike conventional electromagnets, superconducting magnets operate with almost zero electrical resistance when cooled to extremely low temperatures. This allows them to carry massive electrical currents while consuming far less energy.

China has also successfully tested a high-temperature superconducting central solenoid, another critical component often described as the "heart" of a tokamak. The central solenoid generates the plasma current required to initiate and sustain fusion reactions, working alongside the toroidal-field magnet to maintain plasma stability.

How the new magnet improves on earlier designs

Chinese researchers say the new toroidal-field magnet has a volume roughly 1.3 times larger than the equivalent magnet designed for the international ITER fusion project in France. It can also store three times more magnetic energy, enabling stronger magnetic fields for plasma confinement.

The six-year development programme involved advances in superconducting conductor manufacturing, structural engineering, cryogenic systems and quench protection. Researchers say the project has produced dozens of patents and helped establish new industry standards for large-scale superconducting magnet technology.

China's 'Artificial Sun' programme enters next phase

China's Experimental Advanced Superconducting Tokamak (EAST), widely known as the "Artificial Sun", has already set several world records by sustaining ultra-hot plasma for increasingly longer durations. EAST serves as a research platform to test technologies needed for future commercial fusion reactors.

The newly completed magnet, however, is intended for the BEST reactor rather than EAST. BEST is designed to move beyond experimental research by demonstrating sustained burning plasma and eventually producing electricity through controlled nuclear fusion.

When could fusion power become commercially viable?

China expects construction of the BEST reactor to be completed by 2027. If development stays on schedule, researchers hope to demonstrate electricity generation from controlled nuclear fusion around 2030.

Although commercial fusion remains one of science's biggest engineering challenges, advances in superconducting magnet technology are steadily bringing researchers closer to harnessing fusion as a practical source of clean energy.

Why nuclear fusion is seen as the future of clean energy

Unlike conventional nuclear fission, which generates energy by splitting heavy atoms, nuclear fusion produces power by combining light hydrogen isotopes. The process emits no greenhouse gases during operation and generates significantly less long-lived radioactive waste than today's nuclear power plants.

Scientists view fusion as one of the most promising long-term solutions to rising global energy demand. China's latest breakthrough highlights the rapid progress being made in the global race to develop commercially viable fusion energy and brings the vision of an "Artificial Sun" capable of powering cities a step closer to reality.