Determination of tungsten sources in the JET-ILW divertor by spectroscopic imaging in the presence of a strong plasma continuum. (January 2019)

• Record Type: Journal Article
• Authors: Huber, A.; Brezinsek, S.; Kirschner, A.; Ström, P.; Sergienko, G.; Huber, V.; Borodkina, I.; Douai, D.; Jachmich, S.; Linsmeier, C.h.; Lomanowski, B.; Matthews, G.F.; Mertens, P.h.
• Is Part Of: Nuclear materials and energy. Volume 18(2019)
• Page Start: 118
• Page End: 124
• Publication Date: 2019-01
• Subjects: Tungsten erosion -- Tungsten imaging spectroscopy -- W Divertor -- JET-ILW -- PSI -- PFC; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2018.12.009
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: A new algorithm for the subtraction of the continuum radiation was successfully developed and is now used to evaluate the W erosion. The identification of the tungsten atom sources and the measurement of their radiation profiles in front of all plasma-facing components has been performed in JET. The resultant intra-ELM sputtering was of about 7 × 10 18 atoms/ELM in H-mode pulses with an input power of PIN = 21.5 MW. It was observed that intra-ELM sputtering dominated by a factor of 7 over inter-ELM sputtering. Abstract: The identification of the sources of atomic tungsten and the measurement of their radiation distribution in front of all plasma-facing components has been performed in JET with the help of two digital cameras with the same two-dimensional view, equipped with interference filters of different bandwidths centred on the W I (400.88 nm) emission line. A new algorithm for the subtraction of the continuum radiation was successfully developed and is now used to evaluate the W erosion even in the inner divertor region where the strong recombination emission is dominating over the tungsten emission. Analysis of W sputtering and W redistribution in the divertor by video imaging spectroscopy with high spatial resolution for three different magnetic configurations was performed. A strong variation of the emission of the neutral tungsten in toroidal direction and corresponding W erosion has been observed. It correlates strongly with the wetted area with a maximal W erosion at the edge of the divertor tile.