Korean Tokamak Sets Another World Record

January 30, 2021

The Korean tokamak KSTAR has set another world record, holding a 100 million degree plasma continuously for 20 seconds. They are aiming raise this holding time to 5 minutes by 2025.

The KSTAR Research Center at the Korean Institute of Fusion Energy (KFE) announced that, in joint research with Seoul National University (SNU) and Columbia University in the United States, it succeeded in achieving continuous operation of plasma for 20 seconds with an ion temperature higher than 100 million degrees, which was one of the core conditions of nuclear fusion sought in the 2020 KSTAR Plasma Campaign.

The achievement extended the eight-second plasma sustainment time achieved during the 2019 KSTAR Plasma Campaign by more than two times. In its 2018 experiment, KSTAR reached a plasma ion temperature of 100 million degrees for the first time (retention time: about 1.5 seconds).

KFE states "Thus far, there have been other fusion devices that have briefly managed plasma at temperatures of 100 million degrees or higher. None of them broke the barrier of maintaining the operation for ten seconds or longer. This represented the operational limit of a normal conducting device, and it was difficult to maintain a stable plasma state in the fusion device at such a high temperature for a long time."

In its 2020 experiment, KSTAR improved the performance of the internal transport barrier (ITB) mode, one of the next-generation plasma operation modes developed in 2019 and succeeded in maintaining the plasma state for a long period of time, overcoming the existing limits of the ultra-high-temperature plasma operation.

Director Si-Woo Yoon of the KSTAR Research Center at the KFE explained, "The technologies required for long operations of 100 million-degree plasma are the key to the realization of fusion energy, and KSTAR's success in maintaining high-temperature plasma for 20 seconds will be an important turning point in the race for securing the necessary technologies for long high-performance plasma operation, a critical component of a commercial nuclear fusion reactor in the future"

"The success of the KSTAR experiment in long high-temperature operation by overcoming certain drawbacks of the ITB modes brings us a step closer to the development of technologies leading to the realization of nuclear fusion energy," added Yong-Su Na, a professor in the Department of Nuclear Engineering at SNU, who has been jointly conducting research on the KSTAR plasma operation.

KSTAR is going to share its key experiment outcomes in 2020, including this success, with fusion researchers around the world at the IAEA Fusion Energy Conference, currently scheduled to be held in May of 2021. For more information on KFE visit: https://www.kfe.re.kr