A new record for fusion was set by researchers from the U.S. Department of Energy, Princeton Plasma Physics Laboratory, and the French Commission for Alternative Energy and Atomic Energy using the tungsten-walled tokamak WEST.
For 6 minutes, the reactor withstood plasma heated to 50 million °C with a consumption of 1.15 gigajoules of energy. This resulted in 15% more energy than in previous attempts and twice the plasma density. To measure plasma parameters and other process characteristics, the researchers used an X-ray detector inside the tokamak. Extremely refractory tungsten is considered one of the most promising materials for industrial fusion.
«The environment using a tungsten wall is much more complex than using carbon [in other tokamaks]. It’s just the difference between trying to grab a kitten at home and petting a predatory lion,» says Luis Delgado-Aparicio, lead researcher on the project.
Tokamak — a torus-shaped fusion reactor that uses magnetic fields to contain plasma where fusion reactions take place. During fusion, atoms merge and form new ones, which is accompanied by a huge release of energy and temperatures higher than in stars. This reaction is the opposite of nuclear fission, which is used in conventional nuclear reactors.
The challenge of industrial fusion is to continuously maintain a stable reaction with the generation of more energy than is consumed. Fusion does not create waste, as in nuclear fission, and releases much more energy, so it is considered the «holy grail» of energy. Scientists consider the achievement of a steady-state reaction in the experiment an outstanding achievement.