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On the applicability of three and four parameter fits for analysis of swept embedded Langmuir probes in magnetised plasma
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SYSNO ASEP 0565842 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title On the applicability of three and four parameter fits for analysis of swept embedded Langmuir probes in magnetised plasma Author(s) Komm, Michael (UFP-V) RID, ORCID
Adámek, Jiří (UFP-V) RID, ORCID
Cavalier, Jordan (UFP-V) RID, ORCID
Brotánková, J. (CZ)
Grover, Ondřej (UFP-V) ORCID
Hečko, Jan (UFP-V)
Horáček, Jan (UFP-V) RID, ORCID
Matějíček, Jiří (UFP-V) RID, ORCID
Peterka, Matěj (UFP-V) RID, ORCID
Podolník, Aleš (UFP-V) ORCID
Seidl, Jakub (UFP-V) RID
Hron, Martin (UFP-V) RID, ORCID
Pánek, Radomír (UFP-V) RIDNumber of authors 13 Article number 096021 Source Title Nuclear Fusion. - : Institute of Physics Publishing - ISSN 0029-5515
Roč. 62, č. 9 (2022)Number of pages 18 s. Language eng - English Country AT - Austria Keywords fitting ; Langmuir probe ; plasma sheath ; tokamak Subject RIV BL - Plasma and Gas Discharge Physics OECD category Fluids and plasma physics (including surface physics) R&D Projects GA20-28161S GA ČR - Czech Science Foundation (CSF) LM2018117 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Method of publishing Open access Institutional support UFP-V - RVO:61389021 UT WOS 000837837000001 EID SCOPUS 85136141456 DOI 10.1088/1741-4326/ac8011 Annotation The problem of power exhaust is one of the grand challenges of nuclear fusion research today. In order to understand the physics phenomena occurring in the scrape-off layer and the divertor regions of tokamaks, it is essential to correctly determine the divertor plasma parameters, which are often measured by swept Langmuir probes (LPs). While the construction and operation of this diagnostic can be straightforward, the data analysis using three- or four-parameter fits presents a challenge and can potentially lead to erroneous values of electron temperature and ion saturation current. In this work, we present modelling and experiments aimed at determination of conditions for proper analysis of swept LPs using these two fitting models. Particle-in-cell modelling was employed to evaluate the sheath-expansion effects for particular probe geometry and plasma conditions, yielding a semi-empirical rule capable of predicting its magnitude. Experiments with unusually wide range of swept voltage in the divertor of the COMPASS tokamak explored the magnitude of voltage range required for successful analysis with either three or four-parameter fitting. With the use of our new semi-empirical rule, it is possible to improve the four-parameter fit reliability in situations where the available voltage range is limited. In addition, we introduce the tangent method—an independent and fast method of electron temperature estimation, which allows to reliably determine the available voltage range and as such assist more complex methods of probe analysis. Workplace Institute of Plasma Physics Contact Vladimíra Kebza, kebza@ipp.cas.cz, Tel.: 266 052 975 Year of Publishing 2023 Electronic address https://iopscience.iop.org/article/10.1088/1741-4326/ac8011
Number of the records: 1