Enable Recite

Subscribe options

Select your newsletters:

Please enter your email address:

@

Your email address will only be used for the purpose of sending you the ITER Organization publication(s) that you have requested. ITER Organization will not transfer your email address or other personal data to any other party or use it for commercial purposes.

If you change your mind, you can easily unsubscribe by clicking the unsubscribe option at the bottom of an email you've received from ITER Organization.

For more information, see our Privacy policy.

News & Media

Latest ITER Newsline

  • Data | Archiving 20 gigabytes per second—and making it usable

    One of the main deliverables of ITER is the data itself—and there will be a tremendous amount of it to store and analyze. During First Plasma, the highest produ [...]

    Read more

  • Electrical tests | High voltage, high risk

    In the southern part of the construction platform, a one-hectare yard hosts some of the strangest-looking components of the entire ITER installation. Rows of to [...]

    Read more

  • Vacuum vessel | First sector safely docked

    It was 8:00 p.m. on Tuesday 6 April and something quite unusual happened in the ITER Assembly Hall: applause spontaneously erupted from the teams that h [...]

    Read more

  • Remote ITER Business Meeting | Virtual interaction, tangible opportunities

    While the advent of Covid-19 has not stopped the relentless advancement of the ITER Project, it has certainly prompted ingenuity in how ITER conducts its work. [...]

    Read more

  • Manufacturing | Europe completes pre-compression rings

    The French company CNIM (Toulon) has produced a tenth pre-compression ring for the ITER Project on behalf of Fusion for Energy, the European Domestic Agency. Th [...]

    Read more

Of Interest

See archived entries

Promising research

Taming "ill-behaving" fusion plasmas

Certain types of magnetic distortions have proved beneficial in suppressing ELM-type instabilities at the edge of fusion plasmas—periodic bursts of energy that can lead to an accelerated erosion of the divertor and first-wall components. Up to now, though, the ideal 3D topology of the distortion field—among innumerable potential combinations—was unknown. As reported this month in Nature Physics, physicists from Korea and the United States have developed a key predictive capability of how to configure 3D magnetic fields optimally for ELM control, and successfully tested their predictions on the KSTAR tokamak in Korea.

The KSTAR tokamak was the site of the recent experiments to test researchers' predictions. Advanced magnet controls and state-of-the-art imaging diagnostics make this Korean tokamak an ideal device for studying—and learning to mitigate—instabilities called edge localized modes (ELMs). (Click to view larger version...)
The KSTAR tokamak was the site of the recent experiments to test researchers' predictions. Advanced magnet controls and state-of-the-art imaging diagnostics make this Korean tokamak an ideal device for studying—and learning to mitigate—instabilities called edge localized modes (ELMs).
One of the critical challenges in nuclear fusion has been how to tame "ill-behaving" fusion plasmas that tend to intermittently outburst tremendous amounts of heat and particles from plasma edge. These so-called edge-localized-modes (ELMs) have the potential of eroding material from the plasma-facing components—material which can then penetrate and contaminate the plasma.

The physics understanding of ELMs and the development of a methodology to control ELM crashes have thus been a major focus of research in the fusion community for two decades. Among various ELM control means, the most promising method is to apply resonant magnetic perturbation (RMP) to the plasma edge—small magnetic fields that "perturb" the plasma edge, releasing the pressure in a measured way. The RMP technique has proved effective in influencing the unruly high-pressure ELM crashes, but identifying the correct 3D magnetic field configuration—among endless possibilities—has remained a challenge. 

Now, a 14-person team led by physicist Jong-Kyu Park of the Princeton Plasma Physics Laboratory (PPPL), has identified a way to move forward. The research team—comprised of physicists from PPPL (US), the National Fusion Research Institute (NFRI) of Korea, and Oak Ridge National Laboratory (US)—has been able to map out an optimal 3D topology that suppresses ELM crashes at the plasma edge without destabilizing the plasma core.

"We demonstrate the phase-space visualization of the full 3D field-operating windows of a tokamak," explain the authors in their abstract, "which allows us to predict which configurations will maintain high confinement without magnetohydrodynamic instabilities in an entire region of plasmas."

The predictions were tested on the KSTAR tokamak at NFRI with excellent results. Equipped with ITER-like RMP systems, including unique in-vessel mid-row RMP capabilities, and state-of-the-art imaging diagnostics, KSTAR is one of the leading devices in the world for studying ELM-taming using precisely controlled 3D magnetic fields, and clarifying the physics mechanisms during critical transitions.

The researchers' work will allow plasma physicists to not only establish the modus operandi of 3D magnetic fields in order to suppress ELM crashes among innumerous combinations of 3D configurations, but also to contribute to designing the ideal position of 3D field coils in future reactors. The results are important to ITER, which will operate with a 3D coil system that is similarly configured to that of KSTAR.


Please also see the reports published on the NFRI (in Korean) and PPPL websites.


return to the latest published articles