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Latest ITER Newsline

  • ITER Council: project metrics confirm performance

    The governing body of the ITER Organization, the ITER Council, met for the twenty-first time on 15 and 16 November 2017 under the chairmanship of Won Namkung (K [...]

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  • COP 23 | Placing ITER on the global scene

    On the western bank of theRhine and not far from the seat of the UN Climate Change Secretariat, world leaders are discussing how to push ahead for international [...]

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  • Japan's MEXT Minister | Seeing is believing

    On 4 November, ITER received Yoshimasa Hayashi, the Japanese Minister of MEXT—the Ministry of Education, Culture, Sports, Science and Technology with oversight [...]

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  • Architect Engineer | ENGAGE receives prestigious award

    Since 2006, the French 'Grand Prix de l'Ingénierie' has recognized engineering projects and/or teams that are remarkable in terms of scope, innovation, complexi [...]

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  • Sub-assembly tools | One foot inside

    The twin Korean giants already have a foot inside the Assembly Hall—literally. The foot—or 'bottom inboard column' in ITER parlance—is a 4.4-metre-long steel [...]

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Of Interest

See archived articles

The physics behind the transition to H-mode

PPPL physicists Seung-Hoe Ku, Robert Hager, Choong-Seock Chang, and Randy Michael Churchill. (Photo by Elle Starkman) (Click to view larger version...)
PPPL physicists Seung-Hoe Ku, Robert Hager, Choong-Seock Chang, and Randy Michael Churchill. (Photo by Elle Starkman)
H‐mode—or the sudden improvement of plasma confinement in the magnetic field of tokamaks by approximately a factor of two—is the high confinement regime that all modern tokamaks, including ITER, rely on.

It was observed for the first time rather by accident (read more here) and to this day the physics behind H-mode remains not fully understood.

Scientists at the Princeton Plasma Physics Laboratory (PPPL) in the US have made a step in the direction of elucidating the phenomenon by simulating, for the first time, the spontaneous transition of turbulence at the edge of a fusion plasma to H-mode.
The research was achieved with the extreme-scale plasma turbulence code XGC developed at PPPL in collaboration with a nationwide team. This massively parallel simulation, which reveals the physics behind the transition, utilized most of a supercomputer's power—running for three days and using 90 percent of the capacity of Titan at the Oak Ridge Leadership Computing Facility (the most powerful supercomputer for open science in the US).

"After 35 years, the fundamental physics of the bifurcation of turbulence into H-mode has now been simulated, thanks to the rapid development of the computational hardware and software capability," said C.S. Chang, first author of the April Physical Review Letters paper [118, 175001 (2017)] that reported the findings. Co-authors included a team from PPPL, the University of California, San Diego, and the MIT Plasma Science and Fusion Center. Seung-Hoe Ku of PPPL performed the simulation.

Read the full report by John Greenwald on the PPPL website.



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