| 1. |
- Blom, Anders, et al.
(författare)
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Parametrization of the Zeeman effect for hydrogen-like spectra in high-temperature plasmas
- 2002
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335. ; 44:7, s. 1229-1241
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Tidskriftsartikel (refereegranskat)abstract
- We present a method for parametrizing the Zeeman effect in hydrogen-like systems in high-temperature plasmas, where the fine-structure is completely unresolved. The method is based on the observation that the different polarization components behave collectively like separate entities, with simple relations. The entire Zeeman pattern can then be reduced to just three components, whose dependence on the magnetic field and the temperature can be described by only three numerical parameters. This makes it possible to include the influence of the Zeeman effect directly into ion temperature diagnostic procedures with minimal increase in the required computational effort and without the need for pre-calculated correction factors. We have tabulated such parametrizations-which are accurate for a wide range of fields and temperatures, even for cases when the total line-shape is no longer Gaussian-for 44 commonly studied hydrogen-like transitions. The effects of non-statistical population distribution in the upper sub-levels are briefly discussed, and we also note a temperature-dependent wavelength shift of the centre positions of the transitions.
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| 2. |
- Borges, F O, et al.
(författare)
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Weighted oscillator strengths and lifetimes for the SVII spectrum
- 2004
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Ingår i: Journal of Quantitative Spectroscopy & Radiative Transfer. - 0022-4073. ; 83:3-4, s. 751-763
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Tidskriftsartikel (refereegranskat)abstract
- The weighted oscillator strengths (gf) and the lifetimes presented in this work were carried out in a multiconfiguration Hartree-Fock relativistic approach. In this calculation, the electrostatic parameters were optimized by a least-squares procedure, in order to improve the adjustment to experimental energy levels. This method produces gf-values that are in better agreement with intensity observations and lifetime values that are closer to the experimental ones. In this work, we presented all the experimentally known electric dipole S VII spectral lines.
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| 3. |
- G, Möller, et al.
(författare)
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Lifetime measurements of some low-lying quartet levels in al-like sulphur chlorine and iron
- 1989
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Ingår i: Journal de Physique. Colloques. - : EDP Sciences. - 0449-1947. ; 50:C1, s. 1-602
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of some low-lying quartet levels in sulphur, chlorine and iron have been measured using the beam-foil technique. In general, the lifetimes obtained by curve fitting are in agreement with theory. However, the lifetime results for 3s3p(3P)3d 4P04D0 are somewhat higher than predicted, possibly due to the neglection of some of the cascades in the data analysis
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| 4. |
- Giroud, C., et al.
(författare)
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Method for experimental determination of Z dependence of impurity transport on JET
- 2007
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 47:4, s. 313-330
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Tidskriftsartikel (refereegranskat)abstract
- The prediction of impurity peaking in future fusion devices such as ITER necessitates the study of the dependence on Z of the impurity transport in present devices. In this paper we describe a novel technique to determine the transport of impurities with different atomic numbers independently. A technique has been developed that allows simultaneously the measurement of the transport of Ne and Ar in the same discharge while minimizing the systematic errors in the spectroscopic measurements. The reproduction of the charge-exchange measured densities, absolute vaccum ultra-violet line intensities and absolute soft x-ray intensity is achieved in an impurity transport simulation. The method used to estimate the errors on the transport coefficients of neon (Ne) and argon (Ar) is presented. In the plasma region where the diffusion and convection coefficients are determined for hybrid discharges, the transport of Ne and Ar is observed to exceed neoclassical predictions. In the same regions, the diffusion coefficients of both impurities are similar. The convection coefficients are also comparable for Ne and Ar. The peaking of Ne and Ar density profiles are comparable during the period where the intermittent slow reconnecting n = 1 mode is stable in these hybrid discharges.
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| 5. |
- Jupén, Christer, et al.
(författare)
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Additions to the spectra of highly ionized molybdenum, Mo XXIV-Mo XXVIII
- 2003
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Ingår i: Physica Scripta. - 0031-8949. ; 68:4, s. 230-232
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Tidskriftsartikel (refereegranskat)abstract
- We have observed radiation from highly charged molybdenum ions in the JET tokamak plasmas. Spectra were recorded in the wavelength range 70-110 Angstrom, resulting in the classification of 15 new n = 3. Deltan = 0 transitions in Mo XXIV-Mo XXVIII.
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| 6. |
- Jupén, Christer, et al.
(författare)
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Analysis of 3s, 3p, 3d and 4f configurations of Sc XIII and V XV
- 2002
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Ingår i: Physica Scripta. - 0031-8949. ; 66:2, s. 150-158
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Tidskriftsartikel (refereegranskat)abstract
- In spectra obtained from foil-excited and laser-produced plasmas, we have identified 70 new lines as belonging to the spectra of fluorine-like scandium and vanadium ions, Sc XIII and V XV The new lines in the wavelength region from 70 to 600 Angstrom represent 2p(4)3s-3p, 3p-3d and 3d-4f transition arrays. The spectra have been interpreted with the aid of theoretical calculations, and the consistency of our derived 3s, 3p, 3d and 4f energy levels has been checked by means of isoelectronic comparisons.
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| 7. |
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| 8. |
- Jupén, Christer, et al.
(författare)
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The 2p53s, 3p and 3d configurations in neon-like Ti XIII and Fe XVII
- 1984
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Ingår i: Physica Scripta. - 0031-8949. ; 30:2, s. 112-112
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Tidskriftsartikel (refereegranskat)abstract
- Spectra emitted from laser-produced plasmas of scandium, titanium, vanadium and chromium have been recorded in the region 270-600 Å, and lines belonging to the 3s-3p and 3p-3d transition arrays in neonlike ions have been identified. The 2p53s, 3p and 3d energy levels have been derived from the observations for Ti XIII and from solar flare lines for Fe XVII. Hartree-Fock calculations and parametric fits have yielded scaling factors for ab initio energy integrals that make it possible to predicts 3s-3p and 3p-3d wavelengths. Observed and predicted wavelengths for the strongest lines in Sc XII, V XIV, Cr XV and Ni XIX are presented.
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| 9. |
- Jupén, Christer, et al.
(författare)
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The spectrum and term system of SVII
- 2002
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Ingår i: Physica Scripta. - 0031-8949. ; 66:2, s. 140-149
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Tidskriftsartikel (refereegranskat)abstract
- The spectrum of six times ionized sulphur, S VII, has been investigated in the wavelength region 200-4000 Angstrom by means of the beam-foil and laser-produced plasma techniques. The analysis comprises 219 lines of which 105 are newly identified. The present work establishes 123 2s(2)2p(5)nl energy levels of which 66 are new. The level energies are determined with an internal consistency of better than 20 cm(-1). The observed level structure has been investigated by means of parametric calculations. The center-of-gravity ionization energy of the 2s(2)2p(5 2)P limit has been determined to 2 269 410 +/- 60 cm(-1). Of the identified 3s-3p and 3p-3d lines 27 are present in the solar coronal spectrum recorded by the SUMER instrument onboard the SOHO satellite. The present work adds 2 new solar identifications and improved wavelengths of some other solar coronal lines.
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| 10. |
- Martinson, Indrek, et al.
(författare)
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Atomic structure studies using fusion plasmas
- 2003
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Ingår i: Physica Scripta. - 0031-8949. ; 68:6, s. 123-132
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Forskningsöversikt (refereegranskat)abstract
- Atomic spectroscopy plays an important role in fusion research and extensive knowledge of atomic parameters is needed for plasma diagnostics. However, a magnetically confined hot plasma can be considered as a spectroscopic fight source which has some unique properties, including high temperature and low density. Fusion devices can therefore be used to tackle problems in basic atomic physics. This paper reviews the contributions to the structure of atomic ions, which have been obtained by the spectroscopy of fusion plasmas. Studies of highly charged ions, forbidden transitions, QED effects and connections between solar physics and fusion plasma physics will be discussed.
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