Nuclear fusion: Chinese reactor crosses a limit previously thought impossible

Nuclear fusion is back at the forefront of the global scientific scene with an announcement from China that, this time, is not confined to laboratories or specialist journals.

In the EAST reactor, nicknamed the artificial sun, researchers have managed to achieve a result that for decades was considered unattainable: keeping the plasma stable even when it reaches extreme densities. A result that could change the fate of clean energy.

The study, published in Science Advances, focuses on the Experimental Advanced Superconducting Tokamak, one of the world's most advanced fusion reactors. Here, for the first time, what scientists call the 'density limit' has been exceeded: a sort of invisible boundary beyond which the plasma loses its stability and the reaction dies out.

Nuclear fusion works like the heart of a star. To produce energy, the fuel - deuterium and tritium - must be brought to dizzying temperatures, in excess of 150 million degrees. Under these conditions, the denser the plasma, the greater the energy produced. This is a simple, almost intuitive rule, but one that has until now run up against a major problem.

Increasing plasma density meant approaching a dangerous threshold. Once this point was crossed, the plasma became unstable, escaping the control of magnetic fields and reducing the experiment to nothing. This obstacle, for years, held back the race towards commercial nuclear fusion, capable of providing clean, safe and virtually inexhaustible energy.

In the EAST reactor, researchers set the initial gas pressure with extreme precision and stabilised the plasma from the very first moments of its life, reducing the impurities that normally cool it and make it unstable to a minimum. The result is a new 'density-free' state, in which the plasma remains stable even beyond previously accepted theoretical limits.

This is not just about numbers or laboratory records. It's a concrete demonstration that this physical wall, considered insurmountable, can be overcome.

The next step will be to go even further, testing this technique under increasingly extreme conditions. If the results are confirmed, nuclear fusion could finally move beyond the realms of a promise to become a real solution to the energy and climate crisis.

(MP/©GreenMe.it/Translation and adaptation: The Global Nature/Pic: Brice Cooper / Unsplash)