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ELM temperature in JET and COMPASS tokamak divertors
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SYSNO ASEP 0572762 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title ELM temperature in JET and COMPASS tokamak divertors Author(s) Horáček, Jan (UFP-V) RID, ORCID
Tskhakaya, David (UFP-V) ORCID
Cavalier, Jordan (UFP-V) RID, ORCID
Adámek, Jiří (UFP-V) RID, ORCID
Mana, A. C. (FR)
Frassinetti, L. (SE)
Beltrami, A. (IT)
Lukeš, S. (CZ)
Aleiferis, S. (GR)
Matthews, G. (GB)
Komm, Michael (UFP-V) RID, ORCID
Bílková, Petra (UFP-V) RIDNumber of authors 12 Article number 056007 Source Title Nuclear Fusion. - : Institute of Physics Publishing - ISSN 0029-5515
Roč. 63, č. 5 (2023)Number of pages 11 s. Language eng - English Country US - United States Keywords divertor ; plasma ; temperature ; tokamak Subject RIV BL - Plasma and Gas Discharge Physics OECD category Fluids and plasma physics (including surface physics) R&D Projects GA22-03950S GA ČR - Czech Science Foundation (CSF) GA20-28161S GA ČR - Czech Science Foundation (CSF) Method of publishing Open access Institutional support UFP-V - RVO:61389021 UT WOS 000960232600001 EID SCOPUS 85151555439 DOI 10.1088/1741-4326/acbf68 Annotation Analysis of the divertor edge localized mode (ELM) electron temperature at a uniquely high temporal resolution (10−5 s) was reported at the JET tokamak (Guillemaut et al 2018 Nucl. Fusion 58 066006). By collecting divertor probe data obtained during many dozens of ELMs, the conditional-average (CAV) technique yields surprisingly low peak electron temperatures, far below the pedestal ones (70%-99% reduction!) which we, however, question. This result was interpreted through the collisional free-streaming kinetic model of ELMs, by a transfer of most of the electron energy to ions, implying a high tungsten sputtering for unmitigated ELMs in future fusion devices like ITER. Recently, direct microsecond temperature measurements on the COMPASS tokamak, however, showed that the electron temperature peak of ELM filaments measured in the divertor is reduced by less than a third with respect to the pedestal one. This was further confirmed by a dedicated 1D particle-in-cell (PIC) simulation and tends to prove that the pedestal electrons can transfer only their parallel energy to ions (due to low collisionality), thus less than a third, as is predicted by the collisionless free-streaming model. This finding strongly contradicts the JET observations. We have therefore compared the CAV to the direct (microsecond) ball-pen and Langmuir probes measurements in COMPASS and found very good agreement between them. Revisiting the aforementioned JET CAV analysis indeed shows that the electron temperatures are much higher than previously reported, close to those predicted by the PIC simulation, and thus the ion energy seems to not significantly increase in the scrape-off layer. Workplace Institute of Plasma Physics Contact Vladimíra Kebza, kebza@ipp.cas.cz, Tel.: 266 052 975 Year of Publishing 2024 Electronic address https://iopscience.iop.org/article/10.1088/1741-4326/acbf68
Number of the records: 1