EUV spectra of highly-charged ions W<sup>54+</sup>–W<sup>63+</sup>relevant to ITER diagnostics

Ralchenko, Yu.; Draganić, Ilija; Tan, Joseph N.; Gillaspy, John D.; Pomeroy, Joshua M.; Reader, Joseph; Feldman, U.; Holland, Glenn E.

doi:10.1088/0953-4075/41/2/021003

Cited by 118 publications

(129 citation statements)

References 29 publications

(35 reference statements)

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“…Measurements performed at EBITs in the EUV range [31,32] are consistent with the calculations in terms of dominant spectral lines and detailed benchmarks with the data from the Berlin EBIT in the soft X-ray range yield good agreement [33,34]. It has been found in [33,34], that the important spectral features are reproduced by the LR calculations predicting most of the spectral lines within an accuracy of factor of 2, while only a few special spectral lines exhibited larger discrepancies.…”

Section: Observation Of Spectral Featuressupporting

confidence: 64%

Calculation and experimental test of the cooling factor of tungsten

Pütterich¹,

Neu²,

Dux³

et al. 2010

Nucl. Fusion

202

195

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Abstract. The cooling factor of W is evaluated using state of the art data for line radiation and an ionization balance which has been benchmarked with experiment. For the calculation of line radiation, level-resolved calculations were performed with the Cowan code to obtain the electronic structure and excitation cross sections (plane-wave Born approximation). The data were processed by a collisional radiative model to obtain electron density dependent emissions. These data were then combined with the radiative power derived from recombination rates and Bremsstrahlung to obtain the total cooling factor. The effect of uncertainties in the recombination rates on the cooling factor were studied and were identified to be of secondary importance. The new cooling factor is benchmarked, by comparisons of the line radiation to spectral measurements as well as to a direct measurement of the cooling factor. Additionally, a less detailed calculation using a configuration averaged model was performed. It was used to benchmark the level-resolved calculations and to improve the prediction on radiation power from line radiation for ionization stages which are computationally challenging. The obtained values for the cooling factor validate older predictions from literature. Its ingredients and the absolute value are consistent with the existing experimental results regarding the value itself, the spectral distibution of emissions and the ionization equilibrium. A table of the cooling factor versus electron temperature is provided. Finally, the cooling factor is used to investigate the operational window of a fusion reactor with W as intrinsic impurity. The minimum value of ¤ ¦ ¥ § © , for which a thermonuclear burn is possible, is increased by 20% for a W concentration of " !

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Section: Observation Of Spectral Featuressupporting

confidence: 64%

Calculation and experimental test of the cooling factor of tungsten

Pütterich¹,

Neu²,

Dux³

et al. 2010

Nucl. Fusion

202

195

View full text Add to dashboard Cite

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“…(2) and are generally added as a rstorder perturbation correction after self-consistency is obtained. The transverse Breit interaction…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…With some experimental data now available, a detailed analysis of extreme ultraviolet (EUV) spectra of highly charged tungsten ions W 54+ W 63+ obtained with an electron beam ion trap (EBIT) was presented by Ralchenko et al [2]. Gillaspy et al measured the 3s 1/2 −3p 1/2 and the 3s 1/2 −3p 3/2 transitions in Na-like ions with Z ≥ 72, including tungsten, together with the 3s 1/2 −3p 3/2 transition in Mglike and the 3p 1/2 −3d 3/2 transition in Al-like and Si-like ions, at the National Institute of Standards and Technology EBIT facility [3].…”

Section: Introductionmentioning

confidence: 99%

Energy Levels and Spectral Lines for n=3 to n=3 Transitions in Mg-Like Tungsten Ions

Liu

Kang

2015

Acta Phys. Pol. A

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Energies and transitions for allowed (E1) and forbidden (E2, M1, and M2) lines for low-lying congurations in magnesium-like tungsten (W 62+ ) are studied using the multiconguration DiracHartreeFock approach. It is shown that the correlations within the n = 3 complex, quantum electrodynamic and Breit eects are very important for the calculation of ne structure energies. The present results are compared to and agree very well with other theoretical energies, wavelengths, transition probabilities and line strengths previously published for a few lines, and are generally found to be more reliable than previous theoretical predictions. The data for E2, M1, and M2 for transitions between the levels are presented as supplemental material. Results are also compared with other theory, when available.

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“…Figure 1 shows simulated spectra for typical plasma parameters measured in ASDEX Upgrade and predicted for ITER. In very recent EBIT investigations [23,24,25] most of the predicted lines could be identified. However, due to the different electron densities in the EBIT (n e ≤ 10 19 m −3 ) and in the centre of fusion plasmas (n e ≥ 10 20 m −3 ) and the mono-energetic electron beam (EBIT) instead of a Maxwellian distribution, investigations in fusion devices are still indispensable, to explore the composition of the spectra emitted from fusion plasmas.…”

Section: Diagnostic Of W In Fusion Devicesmentioning

confidence: 99%

Benefits and Challenges of the Use of High-Z Plasma Facing Materials in Fusion Devices

Neu

2010

AIP Conference Proceedings

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Abstract.The use of high-Z plasma facing components requires intensive research in all areas, i.e. in plasma wall-interaction, in the physics of the confined plasma, diagnostic, and in material development. Only a few present day divertor tokamaks -mainly Alcator C-Mod and ASDEX Upgrade -gained experience with the refractory metals molybdenum and tungsten, respectively. ASDEX Upgrade was stepwise converted from graphite to tungsten PFCs and in parallel a reduction of the deuterium retention by almost a factor of ten has been observed due to the strong suppression of D co-deposition with carbon. The deuterium retained in W is in line with laboratory results. In order to diagnose W sources and the W content in the main plasma adequate spectroscopic methods had to be developed. As expected from the sputtering threshold of Mo and W, negligible erosion by the thermal divertor background plasma is found in ASDEX Upgrade and Alcator C-Mod under low temperature divertor conditions. However, erosion by fast particles and intrinsic impurities, which additionally might be accelerated in rectified electrical fields observed during ion cyclotron frequency heating, plays an important role. The Mo and W concentrations in the plasma centre are strongly affected by plasma transport and variations up to a factor of 50 are observed for similar influxes. However, it could be demonstrated that sawteeth and turbulent transport driven by central heating can suppress central accumulation. The inward transport of high-Z ions at the edge can be efficiently reduced by 'flushing' the pedestal region caused by frequent edge instabilities. Since with metal walls the edge radiation by low-Z impurities is reduced, it has to be substituted in a pure high-Z device by artificially injected low-Z impurities in order to keep the power load at an acceptable level. Experiments at ASDEX Upgrade suggest that a regime with benign erosion and favourable confinement can be achieved. Extrapolations to ITER and DEMO are difficult since the physics of plasma transport is not yet completely understood, the particle and energy fluxes are orders of magnitude higher and the technical boundary conditions in DEMO strongly differ from those of present day devices.

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EUV spectra of highly-charged ions W⁵⁴⁺–W⁶³⁺relevant to ITER diagnostics

Cited by 118 publications

References 29 publications

Calculation and experimental test of the cooling factor of tungsten

Calculation and experimental test of the cooling factor of tungsten

Energy Levels and Spectral Lines for n=3 to n=3 Transitions in Mg-Like Tungsten Ions

Benefits and Challenges of the Use of High-Z Plasma Facing Materials in Fusion Devices

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EUV spectra of highly-charged ions W54+–W63+relevant to ITER diagnostics

Cited by 118 publications

References 29 publications

Calculation and experimental test of the cooling factor of tungsten

Calculation and experimental test of the cooling factor of tungsten

Energy Levels and Spectral Lines for n=3 to n=3 Transitions in Mg-Like Tungsten Ions

Benefits and Challenges of the Use of High-Z Plasma Facing Materials in Fusion Devices

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EUV spectra of highly-charged ions W⁵⁴⁺–W⁶³⁺relevant to ITER diagnostics