Korean artificial sun sets the new world record of 20-sec-long operation at 100 million degrees

The superconducting fusion device KSTAR, also known as the Korean artificial sun or the Korea Superconducting Tokamak Advanced Research, broke the previous record by successfully holding the high temperature plasma for 20 seconds at an ion temperature of over 100 million degrees (Celsius).

In a joint study with Seoul National University (SNU) and Columbia University of the United States, the KSTAR Research Center at the Korea Institute of Fusion Energy (KFE) announced on November 24 (Tuesday) that it had achieved continuous operation of plasma for 20 seconds with an ion-temperature higher than 100 million degrees, which is one of the core conditions of nuclear fusion in the 2020 KSTAR Plasma Campaign.

Extending the 8 second plasma operation period by more than two times during the 2019 KSTAR Plasma Campaign is a success. The KSTAR first surpassed the plasma ion temperature of 100 million degrees during an experiment in 2018 (retention time: around 1.5 seconds).

Hydrogen isotopes must be put into a fusion device like KSTAR to produce a plasma state where ions and electrons are separated, and ions must be heated and sustained at high temperatures in order to replicate fusion reactions that take place in the sun on Earth.

Other fusion devices have so far succeeded to momentarily control plasma at temperatures of 100 million degrees or greater. None of them succeeded in keeping the procedure going for more than 10 seconds. It was challenging to sustain a stable plasma state in the fusion device for an extended period of time at such high temperatures since it is the operating limit of a normal-conducting device.

The Internal Transport Barrier (ITB) mode, one of the next-generation plasma operation modes created last year, performed better in the KSTAR's 2020 experiment and was able to maintain the plasma state for an extended period of time, surpassing the preexisting restrictions of the ultra-high-temperature plasma operation.

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

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

We are honored to have been a part of such a significant accomplishment accomplished in KSTAR, according to Dr. Young-Seok Park of Columbia University. The efficient core plasma heating made possible by enabling this for such a long time resulted in the 100 million-degree ion temperature, demonstrating the special capabilities of the superconducting KSTAR device and serving as a convincing foundation for high performance, steady state fusion plasmas.

The KSTAR started using the device in August of last year and intends to keep using it until December 10 while conducting a total of 110 plasma experiments, including joint research experiments with domestic and international research organizations on high-performance plasma operation and plasma disruption mitigation.

During the remaining experiment time, the KSTAR Research Center conducts experiments on a number of themes, including ITER investigations, with the goal of resolving challenging issues in fusion research, in addition to the success in high temperature plasma operation.

At the IAEA Fusion Energy Conference, which will take place in May 2020, the KSTAR will discuss the important results of their experiment, including this achievement, with fusion researchers from all around the world.

By 2025, the KSTAR will have achieved its ultimate objective of operating continuously for 300 seconds at an ion temperature greater than 100 million degrees.

"I am so glad to announce the new launch of the KFE as an independent research organization of Korea," said KFE President Suk Jae Yoo. In order to fulfill humanity's aim of realizing nuclear fusion energy, the KFE will continue its heritage of undertaking difficult scientific projects.

The Korea Fusion Exploration (KFE), originally the National Fusion Research Institute, was re-established as an autonomous research institution as of November 20, 2020.