China achieves breakthrough in large-diameter superconducting magnet technology
On November 27, 2025, the Institute of Electrical Engineering at the Chinese Academy of Sciences announced a major breakthrough in superconducting magnet technology. The team successfully developed a large-diameter, high-field general-purpose superconducting magnet with a central magnetic field strength of 16.5 Tesla and an inner aperture of 150 mm. This achievement sets a new national record for similar devices.
As a key platform for strong magnetic field research, the magnet provides both a large operating space and a high-intensity magnetic environment, opening new possibilities in cutting-edge scientific and technological fields.
During development, researchers adopted innovative methods such as hierarchical current density design and superconducting phase ratio regulation. These approaches significantly improved magnetic field utilization and coil stability. Advanced processes including vacuum diffusion heat treatment, high-strength glass fiber composite binding, zonal vacuum pressure impregnation, and micron-level fine winding control helped overcome challenges of high stress and strain in niobium-tin magnets.
Third-party testing confirmed that all technical indicators meet design requirements, with the magnet capable of long-term stable operation. The project was independently developed in China, with full intellectual property rights secured.
The superconducting magnet was developed by the Institute of Electrical Engineering, Chinese Academy of Sciences, headquartered in Beijing. Founded in 1958, the institute specializes in electrical engineering, superconductivity, and applied physics. The magnet measures 150 mm (5.9 inches) in inner diameter and weighs several tons. Development costs are reported in Chinese yuan (CNY) and converted to U.S. dollars (USD); the project is estimated at ¥200 million (about $28 million USD). The magnet's central field strength of 16.5 Tesla is equivalent to more than 300,000 times Earth's magnetic field.
