Scientists in South Korea have achieved a major milestone in nuclear fusion research, by sustaining a fusion reaction at temperatures higher than the core of the Sun for 30 seconds.
The Korea Superconducting Tokamak Advanced Research (KSTAR) facility, also known as the Korean artificial sun, reached a plasma ion temperature of 100 million degrees Celsius on December 24, 2022, according to a press release from the National Research Foundation of Korea.
This is the first time that such a high temperature has been maintained for more than 10 seconds in a fusion device, and it marks a significant step towards the goal of achieving stable fusion power generation.
Nuclear fusion is the process that powers the Sun and other stars, in which hydrogen atoms fuse together to form helium, releasing huge amounts of energy. Scientists have been trying to replicate this process on Earth for decades, as it could provide a clean, safe and virtually limitless source of energy.
However, creating and controlling fusion reactions is extremely challenging, as it requires heating and compressing plasma – a state of matter composed of charged particles – to extreme temperatures and pressures. The plasma must also be confined by strong magnetic fields to prevent it from touching the walls of the reactor and cooling down.
KSTAR is one of several tokamaks – doughnut-shaped devices that use magnetic fields to confine plasma – around the world that are working towards achieving fusion. The most ambitious project is the International Thermonuclear Experimental Reactor (ITER), a multinational collaboration that is building a giant tokamak in France, with the aim of producing 500 megawatts of fusion power from 50 megawatts of input power by 2035.
The KSTAR team said that their achievement was made possible by using a technique called the Internal Transport Barrier (ITB) mode, which reduces heat loss and improves plasma confinement. They also credited their collaboration with researchers from Seoul National University and Columbia University, as well as other domestic and international institutions.
The team plans to continue their experiments with longer plasma operation and higher temperatures, and to share their data and technology with ITER and other fusion projects.
‘The success of achieving 100 million-degree plasma for 30 seconds is one of the core technical capabilities for achieving nuclear fusion, and it will be a great help in accelerating the development of fusion technology,’ said Si-Woo Yoon, director of the KSTAR Research Center at the Korea Institute of Fusion Energy.
