More results are revealed from when the world record in fusion was broken at the British JET facility in 2001. During the experiments, the researchers were able to observe for the first time ever how the fusion reaction itself kept the surrounding fuel warm and thus the reaction itself going. The process is called alpha heating and studying it is central to the possibility of developing fusion power plants in the future.
"The new results provide a stable foundation to build on", says Chalmers researcher Pär Strand, who, together with researchers from KTH and Uppsala University, is part of the large international research team that collaborated on the trials in JET.
Pär Strand has been part of fusion research for many years and leads a research group in plasma physics and fusion energy at Chalmers, where they use computer models to construct the conditions in fusion reactors during operation.
The model for fusion energy is the sun, where large amounts of energy are released when light atoms join and form a new atom through fusion. But to bring about fusion on Earth, the atoms need to be heated to temperatures above 100 million degrees and controlled for a sufficiently long time. No materials can withstand such temperatures, so the resarchers at JET instead uses magnetic fields to keep the super heated gas – plasma – in place in the reactor. In 2021, researchers from the European consortium EUROfusion produced a highly publicized world record for the most energy produced in a single fusion shot, and terabytes of data to be analyzed and modelled for the benefit of ITER and future fusion reactors. A more complete set of results has now been published in a special issue of the journal Nuclear Fusion and at the 29th IAEA Fusion Energy Conference.
“One of our most eye-catching results is the first direct observation of the fusion fuel keeping itself hot through alpha heating. This is the process where high-energy helium ions (alpha particles) coming out of the fusion reaction transfer their heat to the surrounding fuel mix to keep the fusion process going”, says Costanza Maggi, a UKAEA Fellow and former JET Task Force Leader. “Studying this process under realistic conditions is crucial to developing fusion power plants.”
Results for the future
"These are important results, since alpha heating is what will heat up the plasma in future reactors", says Emil Fransson, fusion researcher at Chalmers, who is working on improving computer simulations of how particles move and collide in a fusion reactor.
"When we have full-scale fusion, some of the energy created will be converted into electricity, while the alpha particles will heat the plasma. In today's machines we have other methods of heating, as we have very little fusion in them so far. That's why these experiments are so important, they teach us to understand how this type of heating affects the plasma and the whole machine".
More information about the experiments:
In 2021, the EUROfusion consortium of fusion laboratories around Europe ran a dedicated experimental campaign at the Joint European Torus facility (JET) in Culham, UK. The European consortium designed these experiments to explore the extreme conditions expected in the international ITER fusion energy research project and the fusion power plants to follow.
The researchers reached conditions including temperatures of 150 million degrees Celsius inside the donut-shaped cloud of plasma (hot, charged gas) that is suspended inside JET’s magnetic field cage.
Other important results include control techniques to protect the walls of fusion machines, heating techniques, and ways to recover fusion fuel absorbed in the walls of the machine. The work will prove crucial to operate future fusion experimental machines such as ITER and demonstrates the potential of fusion as a future energy source, say the researchers.
Read more:
Previous news about the fusion record: Long-awaited breakthrough for fusion energy
Contacts
- Professor, Astronomy and Plasma Physics, Space, Earth and Environment