China’s EAST Fusion Reactor Surpasses Long-Standing Plasma Density Limit

Researchers operating the Experimental Advanced Superconducting Tokamak (EAST) in Hefei, China, have published findings showing that fusion plasma can remain stable at densities higher than previously thought possible. This development was reported in the journal Science Advances at the start of 2026.

The EAST facility, managed by the Hefei Institutes of Physical Science under the Chinese Academy of Sciences, is known as China’s “artificial sun” due to its role in fusion research. The latest experiments demonstrated that by carefully controlling the interactions between plasma and the reactor wall, the team was able to surpass the established density limit for tokamak devices.

The research was led by Professor Ping Zhu from Huazhong University of Science and Technology and Associate Professor Ning Yan from the Hefei Institutes of Physical Science. The collaboration also included Aix-Marseille University in France, bringing together expertise from multiple institutions.

During the experiments, the team used electron cyclotron resonance heating (ECRH) at the startup phase and adjusted the initial fuel gas pressure. This approach allowed the researchers to optimize plasma-wall interactions from the beginning of each plasma discharge, which was key to achieving the stable high-density regime.

What the numbers show

• Results were published on January 1, 2026
• EAST achieved steady-state plasma for 1,066 seconds in January 2025
• Previous record was 1,056 seconds in December 2021

The experiments provided the first direct confirmation of the plasma-wall self-organization (PWSO) theoretical model. This model predicts that when plasma-wall interactions are properly balanced, a “density-free regime” can be reached, allowing plasma stability at densities above traditional empirical thresholds.

Before this achievement, EAST had already set records for steady-state high-confinement plasma operation, maintaining plasma for over 1,000 seconds in both 2021 and 2025. These earlier milestones established the facility’s capability for long-duration plasma confinement.

The research team’s findings indicate that the density barrier in tokamak fusion reactors can be overcome through precise control of experimental conditions. The published results show that the plasma remained stable well beyond the limits previously considered fundamental for such devices.

The collaboration between Chinese and French institutions highlights the international nature of fusion research. The involvement of multiple organizations contributed to the successful execution and analysis of the experiments conducted at the EAST facility.

* This article is based on publicly available information at the time of writing.