Today, scientists announced a breakthrough in fusion research: the Experimental Advanced Superconducting Tokamak (EAST), nicknamed the 'Artificial Sun', has experimentally smashed the long-standing plasma density limit. This opens up a new 'density-free zone' that could supercharge the quest for clean fusion energy. 🔥
Think of a tokamak like a magnetic racetrack: super-hot plasma (a state of matter where gas is so hot electrons break free) races around a donut-shaped chamber, guided by powerful magnets. Packing in more plasma usually boosts fusion reactions, but push too hard and the plasma spills out, damaging the walls—what scientists call the density limit.
A research team led by the Institute of Plasma Physics at the Hefei Institutes of Physical Science under the Chinese Academy of Sciences, together with Huazhong University of Science and Technology and Aix-Marseille University in France, dove into why this limit kicks in. Their study, published today in Science Advances, reveals a self-organized plasma-wall interaction model. They pinpointed 'radiation instability' triggered by impurities at the boundary as the key culprit behind the density cap.
Armed with this insight, the team tweaked the plasma conditions to tame the instability and guided the system beyond the old limit—landing it safely in a new 'density-free zone'. It’s the first time anyone has confirmed this zone experimentally in a tokamak.
Why it matters? High-density operation could boost fusion output and make reactors more compact—huge wins for future fusion power plants. While commercial fusion is still on the horizon, this milestone brings us a step closer to harnessing the power of the sun right here on Earth. ☀️
Reference(s):
"Artificial sun" experiment able to break fusion plasma density limit
cgtn.com
