E. Leboucher-Dalimier

ASPECTS OF PLASMA SPECTROSCOPY : RECENT ADVANCES

Abstract Two important recent developments in Stark broadening are presented in this work: The first describes the Frequency Separation Technique (FST), which is motivated by the standard electron-ion separation and has important applications in that, coupled to any of a variety of methods capable of treating the intermediate ion-dynamical regime, (but not capable of treating ion impact), presents a unified and practical solution to the ion-dynamical problem. That is, this technique allows the relaxation of the quasistatic approximation. The second describes recent improvements that allow the accurate calculation of electron impact widths.

Observation of ion-ion correlation effects on emissivity and opacity of hot ultra-dense low Z plasmas

The transmission function and the resulting emissivity and opacity of bound-bound transitions in hot ultra-dense, low Z (aluminum or fluorine) plasmas are investigated in this paper. It is shown that the treatment of both the area-normalized line profiles and the absorption oscillator strengths involved are crucial. Taking account, self-consistently, of all the interactions inside a radiating transient molecule, as proposed in the dicenter code IDEFIX, we computed the photo-excitation cross-sections, the emissivities, the opacities, and then compare the results with those from standard codes. We emphasize the strong dependence of the above quantities with the ionic correlations. A first experiment, devoted to measure opacities and emissivities of hot and ultra-dense aluminum plasmas, has been designed. The interpretation of the results shows the adaptability of the dicenter model for these extreme conditions

Spectral line shapes using the dicenter approach for dense, hot plasmas: hydrogen and helium-like lines

Abstract This paper reports on the spectral line shape of hydrogen and helium-like lines relevant to the quasi-static dicenter model. This treatment is justified for hot dense, moderate Z plasmas. The code IDEFIX developed for the quasi-static dicenter model involves a self-consistent description of the interactions and of the radiative properties. Strong dependence of the transition energies and of the dipole moments on the interionic separation are pointed out and novel density-dependent spectroscopic features such as asymmetries, satellite-like features, molecular transitions are exhibited. The theoretical spectra presented here are discussed in connection with experimental results where these exist.

Width functions for the perturbative dipole impact line-broadening theory with correct unitarity cutoff

Abstract In this work accurate analytic formulas are given that enable the correct determination of the minimum impact parameter ϱ min ( v ) for isolated ion lines in the dipole approximation.

Spectroscopic diagnostics of 2D effects in dense plasmas. Comparison with 2D simulations

A space resolved spectrography and monochromatic imaging have been used for the laser-produced hot dense plasma diagnostics. Results are compared with 2-D plasma simulations. (AIP)