Configuration interaction in statistically complete hybrid-structure atomic models1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 633-638 ◽  
Author(s):  
S.B. Hansen
Keyword(s):  
Fine Structure ◽  
Configuration Interaction ◽  
Hybrid Structure ◽  
Oscillator Strengths ◽  
Small Subset ◽  
Computationally Efficient ◽  
Complex Ions ◽  
International Colloquium ◽  
Laboratory Plasmas ◽  
The Spectator

Configuration interaction can have significant effects on the transition energies and strengths of diagnostically important X-ray emission lines and features. However, including full configuration interaction (CI) effects by computing extensive collections of fine structure (LS term) levels may be computationally prohibitive for complex ions. In this paper, we show that CI effects in a simple ion vary little with the configuration of spectator electrons, and that CI effects in complex ions are fairly consistent from one ionization stage to the next, particularly for highly charged ions. Therefore, we argue that the CI effects within an ion can be approximated by extending the CI effects computed from a small subset of configurations in that ion to all transitions of the type (nlj)–(nlj)′ in that ion, regardless of the spectator electron. This approach to CI enforces consistency between the fine structure and averaged states in hybrid-structure atomic models, which are designed to provide a computationally efficient balance of spectroscopic accuracy and statistical completeness.

The 3s23p3d 3Fo term in the Si-like spectrum of Fe (Fe XIII)1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (4) ◽  
pp. 403-412 ◽  
Author(s):  
Elmar Träbert ◽  
Yasuyuki Ishikawa ◽  
Juan A. Santana ◽  
Giulio Del Zanna
Keyword(s):  
Fine Structure ◽  
Ab Initio Calculations ◽  
Solar Corona ◽  
Ab Initio ◽  
Oscillator Strengths ◽  
Special Issue ◽  
International Colloquium ◽  
10Th International Colloquium ◽  
Laboratory Plasmas ◽  
Cast Doubt

The structure of Si-like ions is discussed for the example of iron (spectrum Fe XIII). The 3s23p3d 3Fo term with its three fine structure levels of very different lifetimes has eluded the early observations. Meanwhile, complementary experimental techniques have permitted to track these levels. Theory has also evolved from approximate techniques to accurate ab initio calculations, the results of which cast doubt on some earlier Fe XIII line identifications and guide the search for and the identification of the correct lines in solar corona spectra.

Tungsten measurement on Alcator C-Mod and EBIT for future fusion reactors1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 591-597 ◽  
Author(s):  
Y.A. Podpaly ◽  
J.E. Rice ◽  
P. Beiersdorfer ◽  
M.L. Reinke ◽  
J. Clementson ◽  
...  
Keyword(s):  
Ion Trap ◽  
Oscillator Strengths ◽  
Continuum Emission ◽  
Tokamak Plasmas ◽  
Ion Temperature ◽  
International Colloquium ◽  
Plasma Facing Components ◽  
Laboratory Plasmas ◽  
Electron Beam Ion Trap ◽  
Theoretical Predictions

Tungsten will be an important element in nearly all future fusion reactors because of its presence in plasma facing components. This makes tungsten a good candidate for a diagnostic element for ion temperature and toroidal velocity measurement, and it makes understanding tungsten emissions important for tokamak power balance. The effect of tungsten on tokamak plasmas is investigated at the Alcator C-Mod tokamak using VUV, bolometry, and soft X-ray spectroscopy. Tungsten was present in Alcator C-Mod as a plasma facing component and through laser blow-off impurity injection. Quasi-continuum emission previously seen at other tokamaks has been identified. Theoretical predictions are presented of tungsten emission that could be expected in future Alcator C-Mod measurements. Furthermore, spectra of highly charged tungsten ions have been studied at the SuperEBIT electron beam ion trap. This emission could prove useful for spectroscopic diagnostics of future high-temperature fusion reactor plasmas.

Plasma polarization spectroscopy of atomic and molecular emissions from magnetically confined plasmas1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 495-501 ◽  
Author(s):  
T. Shikama ◽  
K. Fujii ◽  
S. Kado ◽  
H. Zushi ◽  
M. Sakamoto ◽  
...  
Keyword(s):  
Zeeman Splitting ◽  
Oscillator Strengths ◽  
Balmer Series ◽  
International Colloquium ◽  
Polarization Spectroscopy ◽  
Laboratory Plasmas ◽  
Magnetically Confined ◽  
Band Spectra ◽  
The Magnetic Field ◽  
Α Band

In spectroscopic measurements of magnetically confined torus plasmas, the line-integrated emission along a viewing chord is usually observed. However, by utilizing the dependence of the magnitude of the Zeeman splitting on the emission location, a few localized emissions existing along the viewing chord can be separated. A detailed analysis of the Zeeman split spectral lineshapes then makes it possible to evaluate the local values of the magnetic field strength, population density, temperature, and flow velocity. We have introduced polarization spectroscopy to improve the accuracy in separating the overlapped spectra. The polarization resolved Hα, He I, and H2 Fulcher-α band spectra are measured in the TRIAM-1M tokamak, and the atomic and molecular dynamics are investigated. Further progress in the simultaneous measurements of the Balmer series and Fulcher-α band spectra in LHD, and extension to the CH Gerö band spectra, are briefly presented.

On the interpretation of complex atomic spectra by means of the parametric Racah–Slater method and Cowan codes1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (4) ◽  
pp. 451-456 ◽  
Author(s):  
Jean-François Wyart
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Lanthanide Ions ◽  
Oscillator Strengths ◽  
Effective Parameters ◽  
International Colloquium ◽  
Atomic Spectra ◽  
Laboratory Plasmas ◽  
New Energy ◽  
Electronic Configurations

Theoretical studies of electronic configurations of several lanthanide ions in the Racah–Slater approach were performed with the standard suite of codes by R.D. Cowan, including a fitting of energy parameters. Configuration interaction was considered explicitly in the low configurations and was processed by effective parameters for doubly-excited far configurations. Mean errors lower than 100 cm–1 were obtained. Systematic differences are noticed between radial integrals calculated by ab initio PHFR and the Pfit fitted values. The consistency of the scaling factors SF(P) = Pfit/PHFR and of the effective parameters for far configuration effects is shown. In an application to Tm II, the predicted transition probabilities compared well with line intensities and led to the finding of new energy levels. In Nd II, the configuration 4f5 is identified.

Lines of heavy elements and Fe ii in the UV of CS 31082-0011This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (4) ◽  
pp. 357-359
Author(s):  
B. Barbuy ◽  
C. Siqueira Mello ◽  
M. Spite ◽  
F. Spite ◽  
P. Bonifacio ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Oscillator Strengths ◽  
Heavy Elements ◽  
Special Issue ◽  
International Colloquium ◽  
10Th International Colloquium ◽  
Laboratory Plasmas ◽  
Stable Elements ◽  
R Process

The abundance of heavy r-elements may provide a better understanding of the r-process, and the determination of several reference r-elements should allow a better determination of a star's age. The space UV region (λ < 3000 Å) presents a large number of lines of the heavy elements, and in the case of some elements, such as Bi, Pt, Au, detectable lines are not available elsewhere. The extreme “r-process star” CS 31082–001 ([Fe/H] = –2.9) was observed in the space UV to determine abundances of the heaviest stable elements, using STIS on board Hubble Space Telescope.

The chemical composition of the sun1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (4) ◽  
pp. 327-331 ◽  
Author(s):  
N. Grevesse ◽  
M. Asplund ◽  
A.J. Sauval ◽  
P. Scott
Keyword(s):  
Chemical Elements ◽  
Molecular Data ◽  
Solar Neighborhood ◽  
Spectral Lines ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Solar Photosphere ◽  
International Colloquium ◽  
Laboratory Plasmas ◽  
Selection Of

We have very recently re-determined the abundances of nearly all the available chemical elements in the solar photosphere, from lithium to thorium (Asplund et al. Annu. Rev. Astron. Astrophys. 47, 481 (2009)). This new complete and homogeneous analysis results from a very careful selection of spectral lines of all the indicators of the abundances present in the solar photospheric spectrum, from a discussion of the atomic and molecular data, and from an analysis of these lines based on a new 3D model of the solar outer layers, taking non-LTE effects into account when possible. We present these new results, compare them with other recent solar data as well as with recent results for the solar neighborhood, and discuss some of their most important implications as well as some of the atomic data we still urgently need.

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