Bright EUV lines emitted by highly ionized tungsten ions as diagnostic indicators of the tungsten transport in ITER core plasmas (Te > 7 keV)

In this paper we investigate the possible use of spectral lines from highly ionized tungsten (W) ions to measure transport and other physical properties of ITER plasmas. Firstly, we calculate the fractional abundances of W ions for plasmas having electron temperatures in the 7–40 keV range and an electron density of 10 14 cm −3 . Secondly, we calculate the wavelengths and emissivities versus temperature of the brightest spectral lines expected to be emitted by the W ions at extreme ultraviolet (EUV) wavelengths longer than 45 Å. To complement the grazing incidence spectroscopy technique traditionally used to study such spectra, we propose the use of segmented multilayer-coated telescopes for imaging the ITER plasmas in selected EUV lines, similar to the space-based instruments routinely used to study temperatures, emission measures and motions of 0.1–2 keV solar coronal plasmas.