China has achieved a major milestone in its pursuit of an artificial Sun by completing and testing the world's largest superconducting fusion magnet, a critical component for generating clean, virtually limitless energy through nuclear fusion.
The development represents a significant step in China's goal of producing electricity from fusion power by around 2030, strengthening its position among the countries leading the global race to harness carbon-free fusion energy.
Developed by the Institute of Plasma Physics under the Chinese Academy of Sciences, the toroidal field superconducting magnet is a massive D-shaped structure measuring 21 metres in length, 12 metres in width and weighing 582 tonnes.
What is an artificial Sun?
An artificial Sun is a nuclear fusion reactor designed to replicate the same process that powers the Sun.
It works by fusing hydrogen atoms at temperatures above 100 million°C, releasing enormous amounts of energy without emitting carbon dioxide.
Scientists believe fusion could eventually provide an almost limitless, clean and safe source of electricity.
How did China build the world's largest fusion magnet?
According to researchers, the new magnet is the largest superconducting fusion magnet ever constructed. It has 1.3 times the volume and stores three times more energy than comparable magnets developed for the International Thermonuclear Experimental Reactor (ITER), the world's largest fusion research project.
The magnet generates an extremely powerful magnetic field that confines plasma—a superheated gas reaching temperatures of about 100 million°C—inside the reactor while preventing it from coming into contact with the reactor walls.
Researchers also successfully tested a high-temperature superconducting central solenoid coil, often referred to as the heart of a fusion reactor. Comparable to a spark plug in a car engine, the coil is responsible for initiating and sustaining the plasma required for fusion reactions.
China said both the giant magnet and the central solenoid were developed entirely using indigenous materials and manufacturing capabilities, eliminating dependence on foreign suppliers for these key fusion technologies.
The six-year research programme has resulted in 47 patents and the creation of 25 industry standards.
Constructing the magnet required exceptional engineering precision. It is designed to operate for up to 60 years at temperatures close to minus 269°C while carrying extremely high electrical currents and withstanding intense radiation and mechanical stress.
Engineers also managed to reduce electrical resistance at critical joints to nearly zero, enabling currents exceeding 100,000 amperes to flow with virtually no energy loss—an essential requirement for future commercial fusion reactors.
The breakthrough adds to China's recent advances in fusion research. Earlier this year, the Experimental Advanced Superconducting Tokamak (EAST), often referred to as China's artificial Sun, set a world record by maintaining plasma at 100 million°C for 1,066 seconds, demonstrating the longest sustained fusion conditions achieved so far.
China has outlined a three-phase roadmap for commercial fusion energy. The Burning Plasma Experimental Superconducting Tokamak is expected to be completed by the end of 2027, with the country's first fusion-based electricity generation targeted around 2030.
In the long term, China plans to build the China Fusion Engineering Demonstration Reactor, which could become the world's first fusion demonstration power station.
Despite the achievement, researchers acknowledge that several major challenges remain, including completing the full reactor, conducting long-term testing and proving that fusion reactors can consistently produce more energy than they consume.
Even so, scientists believe each technological advance brings the prospect of virtually unlimited, zero-carbon energy closer to becoming a reality, with the potential to revolutionise electricity generation worldwide.
