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Title: Extreme Ultraviolet Spectra of Few-Times Ionized Tungsten for Divertor Plasma Diagnostics

The extreme ultraviolet (EUV) emission from few-times ionized tungsten atoms has been experimentally studied at the Livermore electron beam ion trap facility. The ions were produced and confined during low-energy operations of the EBIT-I electron beam ion trap. By varying the electron-beam energy from around 30–300 eV, tungsten ions in charge states expected to be abundant in tokamak divertor plasmas were excited, and the resulting EUV emission was studied using a survey spectrometer covering 120–320 Å. It is found that the emission strongly depends on the excitation energy; below 150 eV, it is relatively simple, consisting of strong isolated lines from a few charge states, whereas at higher energies, it becomes very complex. For divertor plasmas with tungsten impurity ions, this emission should prove useful for diagnostics of tungsten flux rates and charge balance, as well as for radiative cooling of the divertor volume. Several lines in the 194–223 Å interval belonging to the spectra of five- and seven-times ionized tungsten (Tm-like W VI and Ho-like W VIII) were also measured using a high-resolution spectrometer.
Authors:
 [1] ;  [2] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Physics Division
  2. Lund Univ. (Sweden). Lund Observatory
Publication Date:
Report Number(s):
LLNL-JRNL-669442
Journal ID: ISSN 2218-2004; ATOMC5
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Atoms
Additional Journal Information:
Journal Volume: 3; Journal Issue: 3; Journal ID: ISSN 2218-2004
Publisher:
MDPI
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 70 PLASMA PHYSICS AND FUSION; EBIT; tokamak divertor; plasma diagnostics; tungsten ions; EUV spectroscopy
OSTI Identifier:
1406456

Clementson, Joel, Lennartsson, Thomas, and Beiersdorfer, Peter. Extreme Ultraviolet Spectra of Few-Times Ionized Tungsten for Divertor Plasma Diagnostics. United States: N. p., Web. doi:10.3390/atoms3030407.
Clementson, Joel, Lennartsson, Thomas, & Beiersdorfer, Peter. Extreme Ultraviolet Spectra of Few-Times Ionized Tungsten for Divertor Plasma Diagnostics. United States. doi:10.3390/atoms3030407.
Clementson, Joel, Lennartsson, Thomas, and Beiersdorfer, Peter. 2015. "Extreme Ultraviolet Spectra of Few-Times Ionized Tungsten for Divertor Plasma Diagnostics". United States. doi:10.3390/atoms3030407. https://www.osti.gov/servlets/purl/1406456.
@article{osti_1406456,
title = {Extreme Ultraviolet Spectra of Few-Times Ionized Tungsten for Divertor Plasma Diagnostics},
author = {Clementson, Joel and Lennartsson, Thomas and Beiersdorfer, Peter},
abstractNote = {The extreme ultraviolet (EUV) emission from few-times ionized tungsten atoms has been experimentally studied at the Livermore electron beam ion trap facility. The ions were produced and confined during low-energy operations of the EBIT-I electron beam ion trap. By varying the electron-beam energy from around 30–300 eV, tungsten ions in charge states expected to be abundant in tokamak divertor plasmas were excited, and the resulting EUV emission was studied using a survey spectrometer covering 120–320 Å. It is found that the emission strongly depends on the excitation energy; below 150 eV, it is relatively simple, consisting of strong isolated lines from a few charge states, whereas at higher energies, it becomes very complex. For divertor plasmas with tungsten impurity ions, this emission should prove useful for diagnostics of tungsten flux rates and charge balance, as well as for radiative cooling of the divertor volume. Several lines in the 194–223 Å interval belonging to the spectra of five- and seven-times ionized tungsten (Tm-like W VI and Ho-like W VIII) were also measured using a high-resolution spectrometer.},
doi = {10.3390/atoms3030407},
journal = {Atoms},
number = 3,
volume = 3,
place = {United States},
year = {2015},
month = {9}
}