Density of atoms in Ar*(3p54s) states and gas temperatures in an argon surfatron plasma measured by tunable laser spectroscopy

Abstract

International audienceThis study presents the absolute argon 1 s (in Paschens's notation) densities and the gas temperature, Tg, obtained in a surfatron plasma in the pressure range 0.6510 mbar, for which the pressure broadening can no more be neglected. Tg is in the range of 480-750 K, increasing with pressure and decreasing with the distance from the microwave launcher. Taking into account the line of sight effects of the absorption measurements, a good agreement is found with our previous measurements by Rayleigh scattering of Tg at the tube center. In the studied pressure range, the Ar(4 s) atom densities are in the order of 1016-1018 m-3, increasing towards the end of the plasma column, decreasing with the pressure. In the low pressure side, a broad minimum is found around 1

Understanding Microwave Surface‐Wave Sustained Plasmas at Intermediate Pressure by 2D Modeling and Experiments

“…The maximum values of the Ar(4 s ) density (not shown here) calculated by the two models in the order of 1–2 × 10 18 m −3 are found at the plasma column ends, which is in agreement with experimental measurements along the z ‐axis in surfatron sustained Ar discharges . The radially averaged density in the discharge center is in the order of 5–6 × 10 17 m −3 .…”

“… and , presenting analytical or modeling research, and Refs . and, presenting experimental or combined theoretical and experimental research). Just to mention some of the groups explicitly, we would like to refer to the pioneering work on the theory of SW propagation in guiding structure with different geometries and on the SW discharge applications done in Montreal, Lisbon, Sofia, Bochum, and Moscow, as well as in a number of collaborations among these groups and thus forming the solid basis for further SW sustained plasma research and applications …”

Measurements and kinetic modeling of atomic species in fuel-oxidizer mixtures excited by a repetitive nanosecond pulse discharge

“…Two partially overlapping absorption transitions, 1s 5 → 2p 7 at ν 0 = 772.38 nm and 1s 3 → 2p 2 at ν 0 = 772.42 nm, can be detected. Figure 8 also shows a synthetic absorption spectrum, calculated using the Voigt line shape profile, with van der Waals broadening factors, Einstein coefficients, and state degeneracies taken from [16]. It can be seen that the synthetic spectrum is in good agreement with the experimental data.…”

Understanding CO2 decomposition in microwave plasma by means of optical diagnostics

“…The reason behind this maximum is that adding molecular gas to an Ar plasma will in first instance lead to a slight decrease of n e and a moderate increase of T e (see, e.g., Wang et al). As discussed in Hubner et al, the high values of T e should favor an efficient excitation of Ar met states, while the low n e values result in a low stepwise ionization of atoms. Therefore, this must lead to an increase of Ar met densities and CO 2 decomposition.…”