Ultra-strong magnet sets world record

Chinese researchers have set a new record by developing an all-superconducting user magnet with a central magnetic field of 35.6 tesla — more than 700,000 times stronger than Earth's magnetic field.

The user magnet, installed in the Synergetic Extreme Condition User Facility in Beijing's Huairou district, is the world's only superconducting magnet capable of providing ultra-strong magnetic fields above 30 tesla for scientific experiments, consolidating China's leadership in high-field magnet technology.

Unlike specialized research magnets, this groundbreaking magnet is designed for open access, facilitating cutting-edge material research in extreme experimental conditions for both domestic and international research teams.

Superconducting magnets, which feature zero electrical resistance, high stability, and low energy consumption when operating at extremely low temperatures, are indispensable for advanced scientific infrastructure, medical imaging, and national defense technologies.

While maintaining a bore diameter of 35 millimeters, the leap in performance was achieved through breakthroughs in core technologies. The Institute of Electrical Engineering of the Chinese Academy of Sciences pioneered advancements in magnet design and construction, while the CAS'Institute of Physics addressed challenges in precision measurement and system integration under extreme conditions.

"In a strong magnetic field and low-temperature environment, a bore diameter of 35 millimeters can already meet the requirements of most experiments, including nuclear magnetic resonance, specific heat measurement, and electrical resistance measurement," said Wang Qiuliang, an academician with the CAS. "Ongoing research aims to increase the magnet's bore diameter to accommodate a wider range of measurement techniques."

"Compared to nonsuperconducting resistive magnets, all-superconducting magnets have extremely low operational costs because superconductors possess zero resistance and incur no energy loss," said Luo Jianlin, a professor at the Institute of Physics.

Luo said that scientists plan to surpass a magnetic field strength of 40 tesla to enhance the magnet's overall performance. They also plan to boost the refrigeration capacity of the liquid helium refrigerator to lower the long-term costs of maintaining a low-temperature environment.

limenghan@chinadaily.com.cn