World’s largest superconducting magnet for fusion reactor unveiled in China

The world’s largest Toroidal Field (TF) superconducting magnet for fusion reactors passed technical acceptance by an expert panel on Saturday in Hefei, capital city of east China’s Anhui Province.

The volume of this magnet, weighing 582 metric tons, is 1.3 times that of the TF magnet used in the International Thermonuclear Experimental Reactor, and its energy storage capacity is three times greater, according to its developers at the Hefei-based Institute of Plasma Physics, Chinese Academy of Sciences.

The magnet, one of the most crucial components of a fusion reactor, is responsible for creating the toroidal magnetic field, which firmly constrains the plasma and reduces the impact and energy loss of high-energy particles on the vacuum chamber walls.

In the future, 16 such magnets will be combined and built together to form a complete Toroidal Field.

“Its function is to confine the plasma, preventing it from hitting the walls within the vacuum chamber. The intensity of its magnetic field is related to the temperature and density required for the plasma in the future. A ring composed of 16 coils will generate a magnetic field of 6.5 teslas,” said Wu Yu, a researcher at Chinese Academy of Sciences’ Institute of Plasma Physics (ASIPP).

The institute has been developing the magnet for six years.

“This coil is the heaviest in the world, with the highest energy storage capacity among all superconducting coils currently. The special stainless steel we are currently using, as well as our insulating materials and superconducting materials, are all domestically produced. This project is realized with 100 percent of domestic products,” said Song Yuntao, head of the ASIPP.

It is one of the two key superconducting magnets related to fusion reactors that were announced by China on the day. The other magnet, the high-temperature superconducting central solenoid coil, completed full-condition parameter testing on the same day.

The summer wheat harvest is in full swing in Qixian County, Shanxi Province, in northern China, and is expected to be completed by the end of June.

A total of 22,000 mu (nearly 1,500 hectares) of wheat have ripened in the county. Harvesters are working across wheat fields, completing wheat gathering, threshing, cleaning, and grain storage.

The county is making the most of the key summer farming period, with coordinated efforts covering planting, field management, and harvesting. About 75 combine harvesters have been put into operation, and the wheat is set to be fully harvested by the end of June.

“Due to autumn rains last year, most of the wheat in Qixian County was sown late. To address this issue, we implemented targeted field management measures, including introducing mixed use of agricultural chemicals against crop diseases and pests, dry and hot wind, and premature aging, and aiding the healthy growth of wheat, which have effectively improved crop conditions. This year, the wheat is growing well and a good harvest is in sight,” said Li Gefei, a senior agronomist with the Qixian County Bureau of Agriculture and Rural Affairs.