Determination of tungsten and molybdenum concentrations from an x-ray range spectrum in JET with the ITER-like wall configuration

• Published in: Journal of physics. B, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2015-07, Vol.48 (14), p.144023-11
• Main Authors: Nakano, T, Shumack, A E, Maggi, C F, Reinke, M, Lawson, K D, Coffey, I, Pütterich, T, Brezinsek, S, Lipschultz, B, Matthews, G F, Chernyshova, M, Jakubowska, K, Scholz, M, Rzadkiewicz, J, Czarski, T, Dominik, W, Kasprowicz, G, Pozniak, K, Zabolotny, W, Zastrow, K-D, Conway, N J
• Format: Article
• Language: English
• Subjects: Charge; crystal spectrometer; heavy impurity; impurity accumulation; Magnetic fields; Plasma currents; Plasmas; radition loss; Reflection; Spectrometers; tokamak; Walls; X-rays
• ISSN: 0953-4075; 1361-6455; 1361-6455
• DOI: 10.1088/0953-4075/48/14/144023

The and 3p-4d inner shell excitation lines in addition to 2p-3s lines have been identified from the spectrum taken by an upgraded high-resolution x-ray spectrometer. It is found from analysis of the absolute intensities of the and lines that W and Mo concentrations are in the range of and , respectively, with a ratio of ∼5% in JET with the ITER-like wall configuration for ELMy H-mode plasmas with a plasma current of 2.0-2.5 MA, a toroidal magnetic field of 2.7 T and a neutral beam injection power of 14-18 MW. For the purpose of checking self-consistency, it is confirmed that the W concentration determined from the line is in agreement with that from the line within 20% and that the plasma effective charge determined from the continuum of the first order reflection spectrum is also in agreement with that from the second order within 50%. Further, the determined plasma effective charge is in agreement with that determined from a visible spectroscopy, confirming that the sensitivity of the x-ray spectrometer is valid and that the W and the Mo concentrations are also likely to be valid.