China’s artificial sun is a nuclear fusion device that produces energy similar to the reactions that take place at the sun’s core. Chinese scientists plan to start operations on the device soon. If successful, scientists could achieve the ultimate goal of cheap, clean, near-limitless, nuclear fusion energy. For a deeper dive into the physics behind this technology, see our explainer on how nuclear fusion works.
The device is called the HL-2M Tokamak. A China National Nuclear Corporation official announced in March 2018 that the construction of HL-2M would be finished by the end of the year. HL-2M Tokamak is part of China’s Experimental Advanced Superconducting Tokamak project, which launched in 2006. In June 2019, the coil system for the HL-2M was installed, and since then, work has gone smoothly.
The sun is powered by nuclear fusion of hydrogen nuclei, which form into helium. Nuclear fusion consists of fusing two lighter atomic nuclei to form a heavier nucleus. This reaction releases a massive amount of energy. Temperatures on the sun are up to 15 million degrees Celsius.
Scientists wanted to recreate this nuclear fusion on Earth, so they heated fuel, different types of hydrogen, to temperatures over 100 million degrees Celsius. The fuel turned into an extremely hot plasma, which had to be confined. One method for confining the plasma that scientists have developed is a donut-shaped device called a tokamak.
The tokamak uses magnetic fields to try to stabilize the plasma so reactions can occur and energy be released. However, plasmas are prone to producing bursts, and the device can get damaged if these touch the reactor wall.
According to James Harrison, a fusion physicist at the United Kingdom Atomic Energy Authority, China’s HL-2M Tokamak differs from other devices because of its magnetic field’s flexibility. When the device is operating at high power, the scientists will be able to tailor it to protect its interior.
Harrison said, “Magnetic confinement fusion devices—such as tokamaks—typically deposit the exhaust heat and particles from the fusion-producing core in a very narrow layer, centimeters-to-millimeters wide, which leads to very high heat and particle loads which can damage the surfaces lining the interior of the device in a reactor; the flexibility available on HL-2M will allow researchers to explore novel solutions to this problem.”
The first stage of HL-2M will involve testing each part of the system individually. Then, Chinese physicists will check integrated systems before beginning any experiments.
Harrison added, “HL-2M will provide researchers with valuable data on the compatibility of high-performance fusion plasmas with approaches to more effectively handle the heat and particles exhausted from the core of the device. This is one of the biggest issues facing the development of a commercial fusion reactor, and the results from HL-2M, as part of the international fusion research community, will influence the design of these reactors.”
At the China Fusion Energy Conference in 2019, the head of the Southwestern Institute of Physics, Duan Xuru, announced that the device would become operational in 2020. He claims the artificial sun will achieve temperatures of over 200 million degrees Celsius, which is about 13 times hotter than the sun’s core.
