C Jupén

The 2p53s, 3p and 3d Configurations in Neon-Like Ti XIII and Fe XVII

Spectra emitted from laser-produced plasmas of scandium, titanium, vanadium and chromium have been recorded in the region 270-600 A, 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.

Isoelectronic comparison of the Al-like 3s23p 2P–3s3p2 4P transitions in the ions P III-Mo XXX

New observations of the 3s23p 2P–3s3p2 4P intercombination transitions in Al-like ions have been made for Cl V from spark spectra recorded at Lund and for Kr XXIV and Mo XXX from spectra obtained at the JET tokamak. The new results have been combined with other identifications of these transitions along the sequence and empirically systematized and compared with theoretical calculations. A set of smoothed and interpolated values for the excitation energies of the 3s3p2 4P levels in P III-Mo XXX is presented.

Laboratory Identification of Temperature Diagnostic Si VII and S IX Lines Present in the Solar Coronal Spectra Measured by SUMER/SOHO

The solar coronal spectrum between 500 and 1610 A and at a height of 21,000 km above the west equatorial limb has recently been recorded by the SUMER instrument on SOHO. Using laboratory spectra obtained with the beam-foil technique, we report the identification of 32 lines observed in this spectrum as 2s22p33s-2s22p33p and 2s22p33p-2s22p33d transitions in Si VII and S IX. Theoretical gA-values and branching ratios for the observed lines, obtained from semiempirical configuration interaction calculations, are also presented. Intensity ratios between the 2s22p43P1-2s22p41S0 forbidden transition and transition from the newly identified high-excitation lines that appear in the same wavelength range are temperature sensitive. Calculations of the intensity ratios between the forbidden line and the high-excitation lines for three temperatures are presented. A comparison between the calculations and some of the SUMER observations is provided.

Transitions in boronlike Ni XXIV, Ge XXVIII, Kr XXXII and Mo XXXVIII and fluorinelike Zr XXXII and Mo XXXIV, observed in the JET tokamak

Spectra of highly ionized Ni, Ge, Kr, Zr and Mo obtained from the JET tokamak have been studied. In total 20 new lines have been classified as n = 2, Δn = 0 transitions in B-like and F-like ions. Among the identified lines are M1 transitions within the 2s22p5 2P ground term of F-like Zr and Mo and within the 2s22p 2P ground term of B-like Mo. Furthermore, for B-like Ni, Kr and Mo, the 2s2p2 4P1/2 and 4P5/2 levels, which decay by spin-forbidden transitions, have been found. From the observed wavelengths 20 new energy levels were determined. The experiments have been complemented with multiconfiguration Dirac-Fock (MCDF) calculations and semiempirical analyses of transition energies in the B I and F I isoelectronic sequences.

Transitions in Multiply Excited FVI and FVII

The transitions 1s2s2p2 5P-1s2p3 5S0 in F VI and 1s2s2p 4P0-1s2p2 4P in F VII have been investigated using the method of beam-foil spectroscopy. The fine-structure separations have been determined for the 1s2s2p2 5P term in F VI and for both 4P terms in F VII. The results are compared with recent theoretical calculations of fine structure, based on relativistic wavefunctions, and with previous experimental data. Lifetime measurements are reported for the 1s2p2 4P5/2 level and the 1s2p3 5S20 level.

Method for experimental determination of Z dependence of impurity transport on JET

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.

Parametrization of the Zeeman effect for hydrogen-like spectra in high-temperature plasmas

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.

Transitions in Al-like, Mg-like and Na-like Kr and Mo, observed in the JET Tokamak

Spectra of highly ionized Kr and Mo, emitted from the JET tokamak plasmas, have been recorded in the region 30-355 ?. Detailed analysis of the n = 3, ?n = 0 transitions in Kr XXIV-XXVI and Mo XXX-XXXII has resulted in a number of new spectral classifications. Some isoelectronic regularities for Al-like and Mg-like ions are discussed.

Identification of 2s22p53p 1S0 decays in the spectra of neon-like ions

The 2p53s 1P1, 3P1–2p53p 1S0 transitions in Ne-like Ti XIII have been identified by beam-foil spectroscopy. The term value derived for the 3p1S0 level is used for improved predictions along the isoelectronic sequence by means of comparison with theoretical calculations. Accurate predictions of the magnetic dipole (M1) transition 2p53s 3P0–3P1 along the sequence are also made.

Beam-foil study of the 2p53s, 3p and 3d configurations of Cl VIII☆

Abstract The spectrum of seven-times ionized chlorine, Cl VIII, has been observed from 300 to 1000 A. 38 lines have been identified as combinations between 23 levels of the 2s 2 2p 5 3s, 3p and 3d configurations. The experimental results are supported by parametric calculations and isoelectronic comparisons. Six additional lines have been identified as combinations between the 2s2p 6 3s, 3p and 3d configurations.