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Divertor infrared thermography on COMPASS

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    0544048 - ÚFP 2022 RIV CH eng J - Journal Article
    Vondráček, Petr - Gauthier, E. - Grof, M. - Hron, Martin - Komm, Michael - Pánek, Radomír
    Divertor infrared thermography on COMPASS.
    Fusion Engineering and Design. Roč. 146, September (2019), s. 1003-1006. ISSN 0920-3796. E-ISSN 1873-7196
    R&D Projects: GA MŠk(CZ) 8D15001; GA MŠk(CZ) LM2015045; GA ČR(CZ) GA16-14228S; GA MŠk(CZ) EF16_019/0000768
    EU Projects: European Commission(XE) 633053 - EUROfusion
    Institutional support: RVO:61389021
    Keywords : Infra-red thermography * Scrape-off layer * Tokamak
    OECD category: Fluids and plasma physics (including surface physics)
    Impact factor: 1.692, year: 2019
    Method of publishing: Limited access
    https://www.sciencedirect.com/science/article/pii/S0920379619301607?via%3Dihub

    A new fast divertor infra-red thermography system was put into operation on COMPASS. It provides full radial coverage of the bottom open divertor with pixel resolution ∼0.6–1.1 mm/px on the target surface and temporal resolution better than 20 μs. The system consists of fast IR camera TELOPS Fast-IR 2K placed in a magnetic shielding box, a positionable holder, a 1 m long IR endoscope consisting of 14 Ge and Si lenses securing off-axis view from an upper inner vertical port and a special graphite divertor tile optimized for IR thermography. The tile is equipped with a heating system allowing tile preheating up to 250 °C. Embedded thermoresistors and a calibration target (a deep narrow hole acting as a black body radiator) allows in-situ calibration of the system including estimation of the target surface emissivity. Furthermore, a roof-top shaped structure on top of the tile increases magnetic field incidence angles above 3 degrees. Laboratory tests of the system performed during its commissioning are presented. The global transmission of the optical system was found to be τ ≈ 40–50%. Poor spatial resolution compared to the design value was observed. Too large surface error of individual lenses was identified as the main cause and re-manufacturing of the most critical lens was suggested. First experimental results obtained using the IR system are presented: divertor heat flux profiles in L-mode with the heat flux decay length λ qomp =2.1−3.3 mm and average H-mode heat flux profiles in an inter-ELM period and during an ELM heat flux maximum with λ qomp ≈0.6 mm and λ qomp ≈6.7 mm, respectively.
    Permanent Link: http://hdl.handle.net/11104/0321106

     
     
Number of the records: 1