Quantitative analysis on tungsten spectra of W6+ to W45+ ions

Abstract

Tungsten ion densities are determined by measuring radial profiles of line emissions in LHD. Zn-(W44+) and Cu-like (W45+) ion densities are determined from line emission at 60.9 A and 127.0 A, respectively. Ion densities of W24+, W25+ and W26+ are also determined from tungsten pseudo-continuum (a so-called unresolved transition array (UTA)) at 29-33 A. Observations of magnetic dipole (M1) forbidden lines at 3377A enable evaluation of the ion density of W27+. In EAST tokamak the tungsten concentration is estimated by a combination of the UTA and total radiation loss. In HL-2A the tungsten influx is evaluated from line emission of W6+ ions at 216.2 A and 261.4 A, which are measured during the tungsten reappearance phase after tungsten laser blow-off. All these results demonstrate a good approach towards quantitative tungsten analysis.