A novel measurement of marginal Alfven Eigenmode stability during high power auxiliary heating in JET

Dataset · Tue Dec 07 04:00:00 EST 2021

DOI:https://doi.org/10.7910/DVN/HGBWIL· OSTI ID:1887436

Tinguely, R. A. ^[1]; Fil, N.; Puglia, P. G.; Dowson, S.; Porkolab, M.; Guillemot, V.; Podesta, M.; Baruzzo, M.; Dumont, R.; Fasoli, A.; Fitzgerald, M.; Kazakov, Ye. O.; Nave, M. F. F.; Nocente, M.; Ongena, J.; Sharapov, S. E.; Stancar, Z.

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1. OSTI

The interaction of Alfven Eigenmodes (AEs) and energetic particles is one of many important factors determining the success of future tokamaks. In JET, eight in-vessel antennas were installed to actively probe stable AEs with frequencies ranging 25-250 kHz and toroidal mode numbers |n| < 20. During the 2019-2020 deuterium campaign, almost 7500 resonances and their frequencies f0, net damping rates \gamma < 0, and toroidal mode numbers were measured in almost 800 plasma discharges. From a statistical analysis of this database, continuum and radiative damping are inferred to increase with edge safety factor, edge magnetic shear, and when including non-ideal effects. Both stable AE observations and their associated damping rates are found to decrease with |n|. Active antenna excitation is also found to be ineffective in H-mode as opposed to L-mode; this is likely due to the increased edge density gradient's effect on accessibility and ELM-related noise's impact on mode identification. A novel measurement is reported of a marginally stable, edge-localized Ellipticity-induced AE probed by the antennas during high-power auxiliary heating (ICRH and NBI) up to 25 MW. NOVA-K kinetic-MHD simulations show good agreement with experimental measurements of f0, \gamma, and n, indicating the dominance of continuum and electron Landau damping in this case. Similar experimental and computational studies are planned for the recent hydrogen and ongoing tritium campaigns, in preparation for the upcoming DT campaign.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• Contributing Organization: JET Contributors
• DOE Contract Number: SC0014264; AC02-09CH11466
• OSTI ID: 1887436
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY