Last month, the Korea Superconducting Tokamak Advanced Research (KSTAR) device, a nuclear fusion reactor known as an "artificial sun", broke the world record by maintaining a plasma for an incredible 20 seconds at an ion temperature of over 100 million degrees Celsius (180 million degrees Fahrenheit), which is one of the core conditions for nuclear fusion from such a device.
KSTAR's progress is staggering. It first reached 100 million degrees Celsius in 2018 but only for 1.5 seconds. In 2019, this was extended to 8 seconds. This has now more than doubled. No other device that has been capable of producing plasma this hot (or hotter) has been able to maintain it for more than 10 seconds.
The record-breaking achievement was possible thanks to a newly developed Internal Transport Barrier Mode. The researchers believe that they will be able to achieve 300 seconds with an ion temperature higher than achieved here over the next five years. A crucial goal in the future development of commercial nuclear fusion reactors.
"The technologies required for long operations of 100 million-degree plasma are the key to the realization of fusion energy," said Si-Woo Yoon, director of the KSTAR Research Center at the Korea Institute of Fusion Energy, said in a statement. "[T]he KSTAR's success in maintaining the high-temperature plasma for 20 seconds will be an important turning point in the race for securing the technologies for the long high-performance plasma operation, a critical component of a commercial nuclear fusion reactor in the future."
This KSTAR run started in August and continued until December 10. The team performed a total of 110 plasma experiments to test the capabilities of the device as well as methods and techniques in injecting and stabilizing the plasma. The experiments were conducted in collaboration with domestic and international partners.
South Korea is one of the members of ITER (originally the International Thermonuclear Experimental Reactor), the engineering megaproject that will be the largest nuclear fusion reactors ever built. Its goal is to demonstrate that it is possible to build a device that can release more energy through nuclear fusion (in a controlled manner), than it takes to create the condition for fusing light atoms in the first place.
The experiments conducted with KSTAR are crucial to informing the development of ITER, which should begin operation in 2025. The results from the 2020 KSTAR run are expected to be presented at the IAEA Fusion Energy Conference in May 2021.
While the joke is that nuclear fusion is always 20 years away, developments such as this over the last decade really show how far this field has come.