A superconducting fusion device, the Korean Superconducting Tokamak Advanced Research or KSTAR, also known as the Korean artificial sun, recently set a new world record. It succeeded in retaining the high temperature of plasma for just 20 seconds that have an ion temperature higher than 100 million degrees Celsius.
Late last month, the KSTAR Research Center at the Korea Institute of Fusion Energy or KFE announced, in combined research with the Seoul National University and Columbia University of the United States, the success of said uninterrupted plasma operation, one of nuclear fusion's core conditions in the 2020 KSTAR Plasma Campaign.
This is such an achievement to extend the eight-second operation of plasma during the 2019 KSTAR Plasma Campaign by over two times.
In its experiment done in 2018, the KSTAR achieved the plasma ion temperature of 100 million degrees Celsius for the first time with a 1.5-second retention time.
The Need to Place Hydrogen Isotopes Inside a Fusion Device
According to a Phys.org. report, to recreate fusion reactions occurring in the sun on Earth, hydrogen isotopes need to be placed inside a fusion device like the KSTAR, for one," to create a plasma state where ions and electrons are separated," and ions need to be heated and retained at high temperatures.
Up to now, there have been other similar devices briefly handled plasma at 100-million degree temperatures or even higher.
As a result, none of these fusion devices broke the blockade of retaining the operation for 20 seconds or longer. It is said to be the operational limit of a regular-conducting device. It was quite a challenge to maintain a stable state of plasma in the fusion device for a long time at such high temperatures.
In an experiment it conducted this year, the KSTAR enhanced the performance of the Internal Transport Barrier or ITB mode, one of the modes for the next generation plasma operation developed in 2019, and succeeded in retaining the plasma state for a longer period, surpassing the current limits of the plasma operation with ultra-high temperature.
According to KSTAR Research Center's Director Si-Woo Yoon at the KFE, the technologies needed for "long operations of 100 million-plasma are the key to the realization of fusion energy." The success of KSTAR in maintaining the high-temperature plasma for 20 seconds will be an essential turning point in a commercial nuclear fusion reaction's component in the future.
The KSTAR experiment's success in the long, "high-temperature operation by overcoming some drawbacks of the ITB modes brings us" one step nearer the development of technologies for the nuclear fusion energy's realization, explained Professor Yong-Su Na, at the Department of Nuclear Engineering, SNU, who has been conjointly doing the study on the KSTAR plasma operation.
Meanwhile, Columbia University's Dr. Young-Seok Park, a contributor to the high-temperature plasma's creation explained, they are honored to be part of such an important achievement made in KSTAR.
Essentially, the 100-million-degree Celsius ion temperature reached by allowing effective core plasma heating for a very long period exhibited the distinctive ability of the "superconducting KSTAR devices and will be acknowledged as a" convincing basis for excellent performance, stable state fusion plasmas, added the expert.
The KSTAR started with its operation of the device in August this year and continued its experiment of the plasma generation until early this month, conducting 110 plasma investigations in all, including "high-performance plasma operation and plasma disruption mitigation experiments," which are collaborative research experiments with both local and overseas research organizations, Phys.org, specified.