China’s nuclear fusion reactor, often called the “artificial sun,” has made a significant breakthrough. It successfully maintained plasma at extreme densities, moving closer to achieving near-limitless clean energy. This advancement was highlighted in a recent statement from the Chinese Academy of Sciences.
In simple terms, nuclear fusion could provide energy without the harmful waste or greenhouse gas emissions associated with fossil fuels. New research, published on January 1 in Science Advances, suggests we might harness this energy source within decades.
However, fusion technology is still in its experimental stage. For over 70 years, scientists have been working on it, and most reactors consume more energy than they produce. Meanwhile, climate change effects are becoming more severe, leading experts to call for immediate action to reduce greenhouse gas emissions. While fusion might not solve today’s climate issues, it holds promise for future energy needs.
Fusion reactors work by fusing light atoms into heavier ones through heat and pressure. They generate energy like the sun, but replicating such high pressures on Earth is a challenge. Reactors like China’s EAST use powerful magnetic fields to contain hot plasma in a donut-shaped chamber. Although no tokamak has achieved self-sustaining fusion yet, EAST is showing progress in maintaining plasma for longer periods.
A key challenge in fusion research has been the Greenwald Limit. This limit determines the maximum density of plasma before it becomes unstable. Higher densities could make fusion easier, but instability can stop the process. The EAST team tackled this by carefully managing plasma interactions, allowing it to stay stable at densities much higher than typical operational ranges.
This isn’t the first time researchers have breached the Greenwald Limit. For instance, the U.S. Department of Energy’s DIII-D facility achieved this in 2022. In 2024, another team at the University of Wisconsin-Madison maintained plasma at ten times the Greenwald Limit. Yet, EAST’s results were unique because they achieved a “density-free regime,” a theoretically stable state where plasma density could rise without instability. This research is based on a concept called plasma-wall self-organization, which explores how plasma interacts with reactor walls.
Efforts from both EAST and U.S. facilities are shaping the future of fusion reactors. Both countries are involved in the International Thermonuclear Experimental Reactor (ITER) program. This collaboration aims to build the world’s largest tokamak in France, expected to begin producing fusion reactions by 2039. The work underway at ITER could lead to practical fusion power plants, making clean energy a reality.
