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

Clementson, Joel; Lennartsson, Thomas LU and Beiersdorfer, Peter (2015) In Atoms 3(3). p.407-421
Abstract
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 angstrom. 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... (More)
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 angstrom. 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 angstrom 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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
spectroscopy, EUV, tungsten ions, plasma diagnostics, tokamak divertor, EBIT
in
Atoms
volume
3
issue
3
pages
407 - 421
publisher
MDPI AG
external identifiers
  • wos:000363981600008
ISSN
2218-2004
DOI
10.3390/atoms3030407
language
English
LU publication?
yes
id
f1691fd0-2a7b-4d1f-92d2-29a3ab9061d1 (old id 8395225)
date added to LUP
2015-12-21 09:41:24
date last changed
2016-04-15 21:05:37
@article{f1691fd0-2a7b-4d1f-92d2-29a3ab9061d1,
  abstract     = {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 angstrom. 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 angstrom 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.},
  author       = {Clementson, Joel and Lennartsson, Thomas and Beiersdorfer, Peter},
  issn         = {2218-2004},
  keyword      = {spectroscopy,EUV,tungsten ions,plasma diagnostics,tokamak divertor,EBIT},
  language     = {eng},
  number       = {3},
  pages        = {407--421},
  publisher    = {MDPI AG},
  series       = {Atoms},
  title        = {Extreme Ultraviolet Spectra of Few-Times Ionized Tungsten for Divertor Plasma Diagnostics},
  url          = {http://dx.doi.org/10.3390/atoms3030407},
  volume       = {3},
  year         = {2015},
}