Electron density and temperature-sensitive x-ray-emission-line ratios for heliumlike Si xiii in the DITE tokamak

Keenan, F. P.; McCann, S. M.; Barnsley, R.; Dunn, James P.; Evans, K. D.; Peacock, N J

doi:10.1103/physreva.39.4092

Cited by 23 publications

(14 citation statements)

References 52 publications

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“…Comparison of the present R(N e ) and G(T e ) line ratios in Mg xi with those measured in a tokamak experiment and previously calculated (Keenan et al 1991 Table 7. Comparison of the present R(N e ) and G(T e ) line ratios in Si xiii with those measured in a tokamak experiment and previously calculated (Keenan et al 1989 (1989,1991) is their inclusion of radiative and dielectronic recombination of the H-like ion and, in the case of Si xiii, also of the inner-shell ionization of the Li-like ion. Regarding the accuracy of the effective collision strengths used in these previous calculations, the data sets were taken from several sources; but specifically for Si xiii, Keenan et al (1987) provide analytic expressions that can be compared with the values of Aggarwal & Keenan (2010) adopted in the present work.…”

Section: Tokamak Benchmarksupporting

confidence: 72%

“…Most appropriately, the present R(N e ) and G(T e ) line ratios for Mg xi and Si xiii can also be compared with tokamak measurements at electron densities and temperatures similar to those of coronal plasmas and with an earlier simulation that attempted to reproduce them (Keenan et al 1989(Keenan et al , 1991. A key aspect of this benchmark is that the electron density and temperature were measured with alternative experimental techniques, namely microwave interferometry and laser-electron scattering, and therefore, a comparison of the spectroscopic line ratios with theory would lead to validations of the experimental accuracy (stated at ∼ 10% in N e and T e ), the spectral computational model and the reliability of the atomic data.…”

Section: Tokamak Benchmarkmentioning

confidence: 96%

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A benchmark of the He-like triplet for ions with 6 ≤Z≤ 14 in Maxwellian and non-Maxwellian plasmas

Rodríguez¹,

Gatuzz²,

Bautista³

et al. 2016

Mon. Not. R. Astron. Soc.

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After an extensive assessment of the effective collision strengths available to model the He-like triplet of C v, N vi, O vii, Ne ix, Mg xi and Si xiii in collisionally dominated plasmas, new accurate effective collision strengths are reported for Ne ix. The uncertainty intervals of the density and temperature diagnostics due to the atomic data errors are also determined for both Maxwell-Boltzmann and κ electron-energy distributions. It is shown that these uncertainty bands limit the temperature range where the temperature line-ratio diagnostic can be applied and its effectiveness to discern the electron-energy distribution type. These findings are benchmarked with Chandra and XMM-Newton spectra of stellar coronae and with tokamak measurements.

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Section: Tokamak Benchmarksupporting

confidence: 72%

Section: Tokamak Benchmarkmentioning

confidence: 96%

A benchmark of the He-like triplet for ions with 6 ≤Z≤ 14 in Maxwellian and non-Maxwellian plasmas

Rodríguez¹,

Gatuzz²,

Bautista³

et al. 2016

Mon. Not. R. Astron. Soc.

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“…For example, the line intensity ratios G(T e ) = (z + x + y)/w and R(n e ) = z/(x + y) of the four prominent x-ray transitions w(1s 2 1 S 0 −1s2p 1 P 1 ), x(1s 2 1 S 0 −1s2p 3 P 2 ), y(1s 2 1 S 0 −1s2p 3 P 1 ) and z(1s 2 1 S 0 −1s2s 3 S 1 ) are useful tools in the diagnostics of the plasma density and temperature (Gabriel & Jordan 1969a,b;Gabriel 1972;Porquet & Dubau 2000;Porquet et al 2001Porquet et al , 2010. These diagnostics have been widely used for solar plasmas Full Table 1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/600/A85 (Doschek & Meekins 1970;Doyle 1980;McKenzie et al 1980;Pradhan & Shull 1981;McKenzie & Landecker 1982;Wolfson et al 1983;Keenan et al 1984Keenan et al , 1987Doyle & Keenan 1986) and tokamak plasmas (Doyle & Schwob 1982;Källne et al 1983;Keenan et al 1989). Reliable line interpretation and plasma modeling require a large amount of accurate atomic data, including energy levels, radiative rates, and collisional rate coefficients related to states up to the n = 5 configurations (Porquet et al 2010;Kallman & Palmeri 2007;Smith & Brickhouse 2014;Beiersdorfer 2015).…”

Section: Introductionmentioning

confidence: 99%

Electron impact excitation for He-like ions withZ= 20–42

Wang

et al. 2017

A&A

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Aims. Spectral lines of He-like ions are among the most prominent features in X-ray spectra from a large variety of astrophysical and high-temperature fusion plasmas. A reliable plasma modeling and interpretation of the spectra require a large amount of accurate atomic data related to various physical processes. In this paper, we focus on the electron-impact excitation (EIE) process. Methods. We adopted the independent process and isolated resonances approximation using distorted waves (IPIRDW). Resonant stabilizing transitions and decays to lower-lying autoionizing levels from the resonances are included as radiative damping. To verify the applicability of the IPIRDW approximation, an independent Dirac R-matrix calculation was also performed. The two sets of results show excellent agreement. Results. We report electron impact excitation collision strengths for transitions among the lowest 49 levels of the 1snl(n ≤ 5, l ≤ (n − 1)) configurations in He-like ions with 20 ≤ Z ≤ 42. The line ratios R and G are calculated for Fe XXV and Kr XXXV. Conclusions. Compared to previous theoretical calculations, our IPIRDW calculation treats resonance excitation and radiative damping effects more comprehensively, and the resulting line emission cross sections show good agreement with the experimental observations. Our results should facilitate the modeling and diagnostics of various astrophysical and laboratory plasmas.

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“…These features arise from impurity elements (e.g., Hsuan et al 1987;Bombarda et al 1988;Beiersdorfer et al 1995;Elton et al 2000;Rosmej et al 2002;Rice et al 1987Rice et al , 1999Rice et al , 2000Rice et al , 2014Rice et al , 2015. The relative intensities Full Tables 1 and 2 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A141 of spectral lines from the n = 2 shell to the ground state have been widely used in temperature and density diagnostics for solar plasma (e.g., McKenzie et al 1979;Wolfson et al 1983;Keenan et al 1984;Doyle & Keenan 1986) and tokamak plasmas (e.g., Källne et al 1983;Keenan et al 1989). Spectral lines decaying from doubly excited helium-like ions are essential in understanding the dielectronic recombination process of hydrogen-like ions.…”

Section: Introductionmentioning

confidence: 99%

Energy levels and transition rates for helium-like ions withZ = 10–36

Guo

Wang

et al. 2016

A&A

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Aims. Helium-like ions provide an important X-ray spectral diagnostics in astrophysical and high-temperature fusion plasmas. An interpretation of the observed spectra provides information on temperature, density, and chemical compositions of the plasma. Such an analysis requires information for a wide range of atomic parameters, including energy levels and transition rates. Our aim is to provide a set of accurate energy levels and transition rates for helium-like ions with Z = 10-36. Methods. The second-order many-body perturbation theory (MBPT) was adopted in this paper. To support our MBPT results, we performed an independent calculation using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Results. We provide accurate energies for the lowest singly excited 70 levels among 1snl (n ≤ 6, l ≤ (n − 1)) configurations and the lowest doubly excited 250 levels arising from the K-vacancy 2ln l (n ≤ 6, l ≤ (n − 1)) configurations of helium-like ions with Z = 10−36. Wavelengths, transition rates, oscillator strengths, and line strengths are calculated for the E1, M1, E2, and M2 transitions among these levels. The radiative lifetimes are reported for all the calculated levels. Conclusions. Our MBPT results for singly excited n ≤ 2 levels show excellent agreement with other elaborate calculations, while those for singly excited n ≥ 3 and doubly excited levels show significant improvements over previous theoretical results. Our results will be very helpful for astrophysical line identification and plasma diagnostics.

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Electron density and temperature-sensitive x-ray-emission-line ratios for heliumlike Si xiii in the DITE tokamak

Cited by 23 publications

References 52 publications

A benchmark of the He-like triplet for ions with 6 ≤Z≤ 14 in Maxwellian and non-Maxwellian plasmas

A benchmark of the He-like triplet for ions with 6 ≤Z≤ 14 in Maxwellian and non-Maxwellian plasmas

Electron impact excitation for He-like ions withZ= 20–42

Energy levels and transition rates for helium-like ions withZ = 10–36

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