title: Image quality method as a possible way of in situ monitoring of in-vessel mirrors in a fusion reactor.
abstract: The plasma-facing (first) mirrors in ITER will be subject to sputtering and/or contamination with rates that will depend on the precise mirror locations. The resulting influence of both these factors can reduce the mirror reflectance (R) and worsen the transmitted image quality (IQ). This implies that monitoring the mirror quality in situ is an actual desire, and the present work is an attempt towards a solution. The method we propose is able to elucidate the reason for degradation of the mirror reflectance: sputtering by charge exchange atoms or deposition of contaminated layers. In case of deposition of contaminants, the mirror can be cleaned in situ, but a rough mirror (due to sputtering) cannot be used anymore and has to be replaced. To demonstrate the feasibility of the IQ method, it was applied to mirror specimens coated with carbon film in laboratory conditions and to mirrors coated with contaminants during exposure in fusion devices (TRIAM-1M and Tore Supra), as well as to mirrors of different materials exposed to sputtering by plasma ions in the DSM-2 plasma stand (in IPP NSC KIPT).
authors: Institute of Plasma Physics, NSC KIPT, Akademichna St. 1, 61108 Kharkov, Ukraine.
authors: V G
authors: VG
authors: Konovalov
authors: Institute of Plasma Physics, NSC KIPT, Akademichna St. 1, 61108 Kharkov, Ukraine.
authors: V S
authors: VS
authors: Voitsenya
authors: Institute of Plasma Physics, NSC KIPT, Akademichna St. 1, 61108 Kharkov, Ukraine.
authors: M N
authors: MN
authors: Makhov
authors: Institute of Plasma Physics, NSC KIPT, Akademichna St. 1, 61108 Kharkov, Ukraine.
authors: I V
authors: IV
authors: Ryzhkov
authors: Institute of Plasma Physics, NSC KIPT, Akademichna St. 1, 61108 Kharkov, Ukraine.
authors: A N
authors: AN
authors: Shapoval
authors: Institute of Plasma Physics, NSC KIPT, Akademichna St. 1, 61108 Kharkov, Ukraine.
authors: S I
authors: SI
authors: Solodovchenko
authors: Institute of Plasma Physics, NSC KIPT, Akademichna St. 1, 61108 Kharkov, Ukraine.
authors: A F
authors: AF
authors: Stan
authors: Institute of Plasma Physics, NSC KIPT, Akademichna St. 1, 61108 Kharkov, Ukraine.
authors: V N
authors: VN
authors: Bondarenko
authors: EUROfusion, D-85748 Garching, Germany; Dutch Institute for Fundamental Energy Research, P.O. Box 6336, 5600 HH Eindhoven, The Netherlands; and Applied Physics Department, Eindhoven University of Technology, Eindhoven, The Netherlands.
authors: A J H
authors: AJ
authors: Donné
authors: Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung-Plasmaphysik, 52425 Jülich, Germany.
authors: A
authors: A
authors: Litnovsky