Soft X-ray bands of highly ionized tungsten, gold and lead emitted by the TEXT tokamak plasma

X ray and EUV spectroscopic measurements of highly charged tungsten ions relevant to fusion plasmas

“…This study complements earlier work on the x ray and EUV spectra of tungsten performed at Tokamaks [1,[3][4][5][6][7] and Electron Beam Ion Traps [8][9][10]. Tokamak sources have been used extensively to provide tungsten spectra, but the spectral information in this case is strongly influenced by the radial profile of electron temperature and density.…”

Tungsten spectra recorded at the LHD and comparison with calculations

“…Resonance 4s -4p transitions in W XLV and W XLVI were also found in the 3 keV spectrum. eventually ending with a Ag-like 4f -5d doublet near 4.4 nm [11] and these have been shown to contribute to the structure appearing in the 5.5 -7.0 nm region which has already been identified as resulting from 4f -5d excitation in W XXII -XXIV [12]. In addition, 4d -5p and 4f -5g transitions also move towards shorter wavelengths with increasing charge and should…”

“…From figures 4 and 5 it is obvious that both 4f -5d and 4f -5g transitions move to shorter wavelengths with increasing ionic charge. The predicted positions of the 4f-5g transitions in W XXII to XXVI are in very good agreement with both the earlier calculations [12] and measurement of the associated spectral bands [12,36]. From our calculations we can associate the unidentified peak at 2.832 nm recorded in [36] as arising from 4f -5g transitions in W XXVIII, while the peak at 2.951 nm previous assigned to WXXIX 4d 10 -4d 9 5p 1 P 1 is seen to possess a significant WXXVII 4f -5g component.…”

“…The radiation was postulated to arise from overlapping transitions in W XXXI -W XXXV [10] but subsequently shown to primarily originate from 4d 10 4f-4d 9 4f 2 and 4d 10 4f-4d 10 5d transitions in Ag-like W XXVIII [11]. Subsequently Finkenthal and co-workers identified features in the 4-7 nm region resulting from groups of unresolved 4d -4f, 5p and 4f -5d, 5g transitions in W XXII through XXVI spectra from the TEXT tokamak [12]. The tungsten was introduced into the plasma discharge by laser ablation.…”

Spectroscopy of highly charged tungsten ions relevant to fusion plasmas

“…In this case, emission may originate from regions with different excitation conditions given by the radial profile of electron temperature and density. The strong influence of plasma transport processes and the occurrence of a large number of ionization states emitting simultaneously further complicates data interpretation and identification [4][5][6][7]. Recently applied high-Z accumulation technique restricts the number of emitting ionization states [8], however the data analysis needs additional support by plasma modeling.…”