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Electromagnetic characteristics of geodesic acoustic mode in the COMPASS tokamak
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SYSNO ASEP 0480872 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Electromagnetic characteristics of geodesic acoustic mode in the COMPASS tokamak Author(s) Seidl, Jakub (UFP-V) RID
Krbec, Jaroslav (UFP-V)
Hron, Martin (UFP-V) RID, ORCID
Adámek, Jiří (UFP-V) RID, ORCID
Hidalgo, C. (ES)
Markovič, Tomáš (UFP-V) RID
Melnikov, A.V. (RU)
Stöckel, Jan (UFP-V) RID
Weinzettl, Vladimír (UFP-V) RID, ORCID
Aftanas, Milan (UFP-V) RID
Bílková, Petra (UFP-V) RID
Bogár, Ondrej (UFP-V) ORCID
Böhm, Petr (UFP-V) RID
Eliseev, L.G. (RU)
Háček, Pavel (UFP-V) RID, ORCID
Havlíček, Josef (UFP-V) RID, ORCID
Horáček, Jan (UFP-V) RID, ORCID
Imríšek, Martin (UFP-V) RID
Kovařík, Karel (UFP-V) RID, ORCID
Bogár, Klára (UFP-V) ORCID
Pánek, Radomír (UFP-V) RID
Tomeš, Matěj (UFP-V)
Vondráček, Petr (UFP-V) RID, ORCIDArticle number 126048 Source Title Nuclear Fusion. - : Institute of Physics Publishing - ISSN 0029-5515
Roč. 57, č. 12 (2017)Number of pages 15 s. Publication form Print - P Language eng - English Country AT - Austria Keywords geodesic acoustic mode ; tokamak ; turbulence ; COMPASS Subject RIV BL - Plasma and Gas Discharge Physics OECD category Fluids and plasma physics (including surface physics) R&D Projects GA16-25074S GA ČR - Czech Science Foundation (CSF) GA14-35260S GA ČR - Czech Science Foundation (CSF) GA16-24724S GA ČR - Czech Science Foundation (CSF) GA15-10723S GA ČR - Czech Science Foundation (CSF) 8D15001 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) LM2015045 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support UFP-V - RVO:61389021 UT WOS 000413136900002 EID SCOPUS 85034417019 DOI 10.1088/1741-4326/aa897e Annotation Axisymmetric geodesic acoustic mode (GAM) oscillations of the magnetic field, plasma potential and electron temperature have been identified on the COMPASS tokamak. This work brings an overview of their electromagnetic properties studied by multi-pin reciprocating probes and magnetic diagnostics. The n = 0 fluctuations form a continuous spectrum in limited plasmas but change to a single dominant peak in diverted configuration. At the edge of diverted plasmas the mode exhibits a non-local structure with a constant frequency over a radial extent of at least several centimeters. Nevertheless, the frequency still reacts on temporal changes of plasma temperature
caused by an auxiliary NBI heating as well as those induced by periodic sawtooth crashes. Radial wavelength of the mode is found to be about 1–4 cm, with values larger for the plasma potential than for the electron temperature. The mode propagates radially outward and its radial structure induces oscillations of a poloidal E × B velocity, that can locally reach the level of the mean poloidal flow. Bicoherence analysis confirms a non-linear interaction of GAM with a broadband ambient turbulence. The mode exhibits strong axisymmetric magnetic oscillations that are studied both in the poloidal and radial components of the magnetic field. Their poloidal standing-wave structure was confirmed and described for the first time in diverted plasmas. In limited plasmas their amplitude scales with safety factor. Strong suppression of the magnetic GAM component, and possibly of GAM itself, is observed during co-current but not counter-current NBI.Workplace Institute of Plasma Physics Contact Vladimíra Kebza, kebza@ipp.cas.cz, Tel.: 266 052 975 Year of Publishing 2018
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