Experimental evidence of very short power decay lengths in H-mode discharges in the COMPASS tokamak

0581974 - ÚFP 2024 RIV US eng J - Článek v odborném periodiku
Hečko, Jan - Komm, Michael - Šos, Miroslav - Adámek, Jiří - Bílková, Petra - Bogár, Klára - Böhm, Petr - Jaulmes, Fabien - Mysiura, Illia - Tomeš, Matěj - Vondráček, Petr - Hron, Martin - Pánek, Radomír
Experimental evidence of very short power decay lengths in H-mode discharges in the COMPASS tokamak.
Plasma Physics and Controlled Fusion. Roč. 66, č. 1 (2024), č. článku 015013. ISSN 0741-3335. E-ISSN 1361-6587
Grant CEP: GA MŠMT(CZ) LM2018117; GA MŠMT(CZ) EF16_013/0001551; GA ČR(CZ) GA19-15229S
GRANT EU: European Commission(BE) 101052200
Institucionální podpora: RVO:61389021
Klíčová slova: divertor heat flux * H-mode * power decay length * scaling * sol
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 2.2, rok: 2022
Způsob publikování: Open access
https://iopscience.iop.org/article/10.1088/1361-6587/ad08f0

Analysis of heat fluxes in scrape-off layer (SOL) plasma is important for the prediction of divertor tile heat loads in future reactor-sized tokamak machines. Typically, the radial heat flux profile can be accurately characterized by the decay length parameter λ q . The predictions are then based on the dependence of λ q on plasma and machine parameters. In recent years, several empirical scaling models were derived from a collective database of decay lengths observed in several large tokamaks as well as two spherical tokamaks. Most recently, a report from the TCV tokamak showed a deviation from several of the proposed models (Maurizio et al (TCV team) 2021 Nucl. Fusion 61 024003). In this work, ∼ 100 edge plasma profiles of ELMy H-mode discharges were collected from the COMPASS tokamak database for heat flux analysis. The COMPASS tokamak has a similar machine size and plasma parameters to the TCV tokamak, offering a valuable comparison. The λ q was measured in both downstream and upstream SOL utilizing a divertor probe array validated by an IR camera and Thomson scattering diagnostics. A comparison with the predictions of several scaling models indicated an occurrence of anomalously short (by a factor of 2-5) inter-ELM power decay lengths in both upstream and downstream, as well as a difference in λ q between these two regions. Possible causes related to the accuracy of magnetic reconstruction were eliminated and physics-based sources of apparent compression effects were hypothesized as a motivation for future research.
Trvalý link: https://hdl.handle.net/11104/0350110