In this paper, the transportation of nitrogen atoms in a flowing post-discharge of molecular nitrogen at atmospheric pressure is studied. The axial variation of the density of nitrogen atoms is modelled and compared with measurements. A relatively high initial density, i.e. several 1014 atoms/cm3, is obtained by this approach, showing also that the main losses are caused by volume and surface recombination during transportation. A low value is found for the recombination probability of the used polyamide surface (around some 10−4) allowing therefore quite long transportation times and distances.

All the Thomas–Fermi approaches to the thermodynamics and atomic physics properties of dense and ionized matter consisting of a single element are systematically derived and compared within a density-functional theoretical framework. The corresponding results are contrasted to those of the average atom model by using similar approximations for exchange, correlation, and gradient corrections. Emphasis is led on equations of state, ionization, level shifts, and radial moments. The same numerical algorithms are used to unravel similar trends or identify specific ones, in terms of density and temperature variations. The most sophisticated Thomas–Fermi–Dirac–Weizäcker method yields the closest results to the hybrid average atom model using quantized bound states. Parameters ranges of potential interest for inertially confined thermonuclear fusion stress out density in the 0.1–10 times the solid, and temperature up to 10 keV.

The transportation of species in a high velocity (∼10 3 cm s −1 ) flowing corona afterglow of molecular nitrogen at atmospheric pressure with added NO as impurity (<10 −5 ) is studied. The variation of species densities along 50 cm downstream of the discharge in an 8 mm inner diameter tube is modelled and compared with emission spectroscopy measurements. It is shown that, according to a quite simple O and NO kinetic mechanism for such a gas composition in the post discharge, N 2 (A) concentration can be obtained from the emissions of the NO γ band at 247.9 nm and the NO β band at 320.7 nm using a low resolution spectrometer (1 nm). The validity of both the measurement technique and of the assumed creation and loss mechanisms of N 2 (A) are demonstrated. An empirical relationship using the ratios of two line intensities has been plotted for several hundred points. The N 2 (A) concentration thus obtained, around 10 11 cm −3 , depending on the experimental conditions, is consistent with the results of direct measurements using the N 2 Vegard-Kaplan system at 260.4 nm.