First Identification of New X-Ray Spectra of Mo39+, Mo40+, W43+, W44+ and W45+ on EAST

TL;DR

This paper reports the first high-resolution X-ray spectra of specific molybdenum and tungsten ions observed on EAST, providing new spectral lines crucial for understanding impurity transport in fusion plasmas.

Contribution

The study presents the first experimental identification of new X-ray spectral lines of Mo39+, Mo40+, W43+, W44+ and W45+ on EAST, confirmed by high-resolution spectroscopy and theoretical models.

Findings

New spectral lines of Mo39+, Mo40+, W43+, W44+ and W45+ identified.

Spectral lines are detectable at specific electron temperatures (6 keV and 12.9 keV).

Experimental results agree well with theoretical predictions from FAC and FLYCHK.

Abstract

New high-resolution x-ray spectra of Mo39+, Mo40+, W43+, W44+ and W45+ have been carefully confirmed for the first time by use of the x-ray imaging crystal spectrometer (XCS) in Experimental Advanced Superconducting Tokamak (EAST) under various combined auxiliary heating plasmas conditions. Wavelength of these new x-ray spectra is ranged from 3.895 {\AA} to 3.986 {\AA}. When core electron temperature (Te0) reaches 6.0 keV, Mo39+ and Mo40+ lines of 3.9727, 3.9294 and 3.9480 {\AA} can be effectively detected on XCS for EAST; meanwhile, line-integrated brightness of these spectral lines of Mo39+ and Mo40+ is very considerable when electron temperature reaches 12.9 keV. Multi-components spectral lines for W43+, W44+ and W45+ have also been identified when Te0 reaches 6 keV. Parts of spectral lines, such as Zn-1, Cu-2, Cu-4a, Cu-4d and Cu-5 lines of tungsten, are first observed experimentally. When electron temperature reaches 12.9 keV, line-integrated intensity for part of these spectral lines of W43+, W44+ and W45+ are considerable. These experimental results and theoretical predictions from FAC and FLYCHK codes are in good general agreement. These new spectral lines, obtained on XCS for EAST, are vital for deeply uncovering the mechanisms of ion and electron thermal, high-Z impurity and momentum (anomalous) transport to achieve the advanced steady-state operation scenarios for ITER and CFETR.