Taking a Step Forward in Fusion Energy Tech
The Korean artificial sun, known as KSTAR, recently set a new record for plasma operation time. This achievement came shortly after it received upgrades to its diverters, which are critical components that come into contact with the plasma, by switching to tungsten monoblocks.
The Korea Institute of Fusion Energy (KFE) reported that during its latest plasma campaign, which lasted from December 2023 to February 2024, it was able to maintain plasma at the incredibly high temperature of 100 million degrees Celsius for 48 seconds. Furthermore, KSTAR reached a high confinement mode (H-mode), a state crucial for efficient fusion, for more than 100 seconds, marking a significant milestone in fusion energy research.
To make fusion energy a reality, we need to master the tech that can keep plasmas—where fusion reactions happen most intensely—at high temperatures and densities for extended periods. That’s why fusion researchers, including those working with machines like KSTAR, are doing a ton of experiments with different plasma setups to nail this down.
KSTAR, a cutting-edge superconducting tokamak, is at the forefront of research into long-duration plasma operations. Back in 2018, KSTAR hit a groundbreaking milestone by heating plasma up to 100 million degrees Celsius for the first time. Pushing the envelope further, in 2021, it set another record by maintaining plasma at this blistering ion temperature of 100 million degrees for a full 30 seconds.
In their most recent experiment series, the team behind KSTAR really knocked it out of the park by keeping their plasma—the ultra-hot stuff where all the fusion magic happens—going strong for 48 whole seconds at an eye-watering ion temperature of 100 million degrees. How did they pull off this stellar feat? By giving their plasma heating systems a major upgrade and getting smarter about how they manage and control plasma that’s hotter than the center of the sun. Thanks to these smart moves, they’ve set a new world record for keeping plasma this hot, this long. It’s like setting a new speed record in space travel, but for fusion energy.
Additionally, the KSTAR research group expertly managed to sustain the high confinement mode, or H-mode, for an uninterrupted span of 102 seconds. This particular mode is fundamental for maintaining plasma states at both high temperatures and densities. A key factor in achieving this was the strategic update made to KSTAR’s divertors in 2023, transitioning them to tungsten material. When compared to the former carbon-based divertors, the new tungsten divertors demonstrated a mere 25% increase in surface temperature when subjected to equivalent heat loads. This improvement is critical, offering substantial benefits for operations that require long-duration pulses at high heating capacities.
Through their meticulous experiments, the team behind KSTAR has conclusively demonstrated the efficacy of transitioning to tungsten divertors, confirming their operational success. Additionally, they have verified that critical aspects of KSTAR, including the heating, diagnostic, and control systems, have upheld the system reliability essential for extended plasma operations.
Dr. Si-Woo Yoon, the brains behind the KSTAR Research Center, couldn’t hide his enthusiasm when he said, “Despite being the first experiment run in the environment of the new tungsten divertors, thorough hardware testing and campaign preparation enabled us to achieve results surpassing those of previous KSTAR records in a short period.” He was keen to point out that this was just the beginning, adding, “To achieve the ultimate goal of KSTAR operation, we plan to sequentially enhance the performance of heating and current drive devices and also secure the core technologies required for long-pulse high performance plasma operations.” It’s clear that the team is on an upward trajectory, with their eyes set firmly on the prize of making fusion energy not just a dream, but a reality.
The overarching objective for KSTAR is to attain an impressive duration of plasma activity — specifically, maintaining it for 300 seconds at ion temperatures exceeding 100 million degrees. To reach this ambitious target, the KSTAR team has dedicated its efforts towards pivotal research domains and the enhancement of device functionalities. Essential steps towards this goal encompass the integration of more tungsten components that directly interact with the plasma and the adoption of cutting-edge artificial intelligence technology for real-time feedback control. These advancements are crucial for refining the performance and capabilities of the device.
Dr. Suk Jae Yoo the President of KFE, said “this research is a green light for acquiring core technologies required for the fusion DEMO reactor (and) we will do our best to secure core technologies essential for the operation of ITER and the construction of future DEMO reactors.”
Alright, so here’s the scoop in a way that’s easy to get. The brainy folks working on the KSTAR project, alongside some sharp minds from PPPL in the USA, figured out a pretty nifty trick using KSTAR’s outer magnetic rings. They cooked up a plan, an error field (EF) optimization model, to keep things stable inside the plasma, right where all the action happens. You know, keeping the wild and rowdy bits from causing too much of a ruckus both at the edge and smack dab in the middle. They ran a bunch of tests and simulations to make sure their idea was solid. And guess what? It was so good they even got to brag about it in “Nature Communications” in February 2024, calling their work “Tailoring tokamak error fields to control plasma instabilities and transport.” In simpler terms, they found a way to smooth out the rough edges in the plasma, making it more stable and easier to work with. Pretty cool, huh?