China has announced another breakthrough in the development of thermonuclear energy. An experiment reported in Science Advances on January 1, 2026 notes that the Experimental Advanced Superconducting Tokamak (EAST tokamak), called the “Artificial Sun” project, has had success. In deuterium-tritium fusion, the fuel must be heated to about 13 keV (150 million kelvin) to reach optimal conditions. At such temperatures, the amount of fusion power produced increases with the square of the plasma density. Most tokamak experiments are characterized by an upper density limit, at which point the plasma becomes unstable, which has always proven an obstacle to fusion development. This results from the plasma-wall interactions.
Science Daily on Jan. 4 reports on the new achievements. According to a new theory, known as plasma-wall self-organization (PWSO), a density-free regime can be achieved when the interaction between the plasma and the reactor’s metallic walls reaches a carefully balanced state. This was first proposed by D.F. Escande from the French National Center for Scientific Research and Aix-Marseille University, and was used in recent EAST experiments. The researchers at EAST carefully controlled the initial fuel gas pressure and applied electron cyclotron resonance heating during the startup phase of each discharge, allowing the plasma density to increase steadily by the end of startup. Under these conditions. EAST was able to enter a density-free regime, where stable operation was maintained even at densities far exceeding the previous limits. “The findings suggest a practical and scalable pathway for extending density limits in tokamaks and next-generation burning plasma devices,” said Professor Zhu Ping, one of the leaders of the experiment at Huazhong University of Science and Technology.
