Signal Nuclear Fusion Breakthroughs Continue: KSTAR 102s, SPARC, EAST Density-Free Regime

Summary

Korea's KSTAR sustained 100-million-degree plasma for 102 seconds in February 2026, more than doubling its own 48-second record. Separately, China's EAST tokamak entered a "density-free regime" in which plasma remained stable at densities far exceeding previous limits, in research led by Prof. Ping Zhu of Huazhong University of Science and Technology and Associate Prof. Ning Yan of the Hefei Institutes of Physical Science, published in Science Advances on 1 January 2026. The EAST team achieved this by carefully controlling initial fuel gas pressure and applying electron cyclotron resonance heating during the startup phase of each discharge, reducing impurity buildup and energy losses. The results confirmed the plasma-wall self-organization (PWSO) theory originally proposed by D.F. Escande and French collaborators. Researchers plan to apply the same approach during high-confinement operation on EAST to reach the density-free regime under high-performance plasma conditions. These results came alongside progress at SPARC, shifting fusion timelines toward the next decade.