Observation and Line Analysis of Tungsten, Molybdenum and Copper Spectra at 20-150Å Emitted from Experimental Advanced Superconducting Tokamak (EAST) Plasma

Abstract

Complex spectra of tungsten (W) and molybdenum (Mo) unresolved transition arrays (W-UTA and Mo-UTA) are frequently observed with isolated W, Mo and copper (Cu) lines at 20-150Å wavelength range in EAST plasmas with limiter configuration. The high-Z impurity ions of W, Mo and Cu enter the plasma through an unavoidable plasma-wall interaction at inboard Mo first wall and outboard W/Cu limiter. The spectra were observed with a fast-time-response extreme ultraviolet (EUV) spectrometer and line identification was carefully performed referring our previous works. As a result, W-UTA at 46-64Å and Mo-UTA at 68-96Å are found to be composed of W²⁷⁺-W⁴⁵⁺ and Mo¹⁶⁺-Mo³⁰⁺ ions, respectively. The Cu spectra from Cu¹⁰⁺-Cu¹³⁺ ions are also found in wavelength range of 135-150 Å. In the analysis radial profiles of the impurity spectra are taken into account in determining the charge state in addition to the time behavior.