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DOE OSTI · 3025772

Pedestal origin and extrapolation of high-density small edge-localised-modes peak parallel energy fluence in ITER and SPARC

Perillo, Renato [Univ. of California, San Diego, La Jolla, CA (United States)] (ORCID:0000000166965970)·Lasnier, Charles [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]·Boedo, Jose [Univ. of California, San Diego, La Jolla, CA (United States)]·Eich, Thomas [Commonwealth Fusion Systems, Devens, MA (United States)]·Li, Zeyu [General Atomics, San Diego, CA (United States)]·Redl, Andreas [Commonwealth Fusion Systems, Devens, MA (United States)]·Khabanov, Filipp [Univ. of Wisconsin, Madison, WI (United States)] (ORCID:0000000260042005)·Marini, Claudio [Univ. of California, San Diego, La Jolla, CA (United States)] (ORCID:0000000348197765)·McLean, Adam [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]·Glass, Fenton [General Atomics, San Diego, CA (United States)]·Ravensbergen, Timo [ITER Organization, St. Paul Lez Durance (France)]·Rizkallah, Rabel [Univ. of California, San Diego, La Jolla, CA (United States)]·Rudakov, Dmitry [Univ. of California, San Diego, La Jolla, CA (United States)]·Traverso, Peter [Oak Ridge Associated Universities (ORAU), Oak Ridge, TN (United States)]
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Abstract

Experimental analysis and simulations with the BOUT++ code show that small edge-localised modes (ELMs) in reactor-relevant high-density regimes originate in a region close to the separatrix and only marginally perturb the pedestal structure. The measured divertor peak parallel energy fluence (ε ∥,peak ) for a database of small ELM scenarios in DIII-D and ASDEX Upgrade can be reproduced, within 40 % accuracy on average, if an ad hoc modification of the Eich peak parallel ELM energy fluence model is applied to account for the small ELM pedestal birth location. This allows for first-order extrapolation of small-ELM divertor ε ∥,peak to ITER and SPARC, resulting in values that satisfy the nominal melting threshold of tungsten monoblocks of 12 MJ m −2 . The findings reported in this study, both via modelling and direct measurements, constitute a step forward in assessing small ELMs in high edge-collisionality scenarios as a viable plasma regime for the operation of next-generation fusion machines.

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Perillo, Renato [Univ. of California, San Diego, La Jolla, CA (United States)] (ORCID:0000000166965970), Lasnier, Charles [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Boedo, Jose [Univ. of California, San Diego, La Jolla, CA (United States)], Eich, Thomas [Commonwealth Fusion Systems, Devens, MA (United States)], Li, Zeyu [General Atomics, San Diego, CA (United States)], Redl, Andreas [Commonwealth Fusion Systems, Devens, MA (United States)], Khabanov, Filipp [Univ. of Wisconsin, Madison, WI (United States)] (ORCID:0000000260042005), Marini, Claudio [Univ. of California, San Diego, La Jolla, CA (United States)] (ORCID:0000000348197765), McLean, Adam [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Glass, Fenton [General Atomics, San Diego, CA (United States)], Ravensbergen, Timo [ITER Organization, St. Paul Lez Durance (France)], Rizkallah, Rabel [Univ. of California, San Diego, La Jolla, CA (United States)], Rudakov, Dmitry [Univ. of California, San Diego, La Jolla, CA (United States)], Traverso, Peter [Oak Ridge Associated Universities (ORAU), Oak Ridge, TN (United States)]. 2026-03-31. Pedestal origin and extrapolation of high-density small edge-localised-modes peak parallel energy fluence in ITER and SPARC. https://doi.org/10.1017/s0022377826101433

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