Density of atoms in Ar*(3p{sup 5}4s) states and gas temperatures in an argon surfatron plasma measured by tunable laser spectroscopy
- LIPhy, Universite Joseph Fourier and CNRS, UMR 5588, Grenoble F-38041 (France)
This study presents the absolute argon 1 s (in Paschens's notation) densities and the gas temperature, T{sub g}, obtained in a surfatron plasma in the pressure range 0.65<100 mbar. The absorption signals of 772.38, 772.42, 810.37, and 811.53 nm lines, absorbed by atoms in 1s{sub 3}, 1s{sub 4,} and 1s{sub 5} states, were recorded with two tunable diode lasers. T{sub g} is deduced from the absorption line shapes when scanning the laser wavelengths. The line profile, which is a Doppler broadening dominated Gaussian at gas pressures of p<10 mbar, changes to a Voigt shape at p>10 mbar, for which the pressure broadening can no more be neglected. T{sub g} 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 T{sub g} at the tube center. In the studied pressure range, the Ar(4 s) atom densities are in the order of 10{sup 16}-10{sup 18} m{sup -3}, increasing towards the end of the plasma column, decreasing with the pressure. In the low pressure side, a broad minimum is found around 10<20 mbar and hence the Ar(4 s) atom densities increase slightly with rising pressure. For the studied pressure range and all axial positions, the density ratio: 1s{sub 5}/1s{sub 4}/1s{sub 3} is very close to a Boltzmann equilibrium by electron impact mixing at the local T{sub e}, which was previously measured by Thomson scattering. The Ar(4 s) densities are successfully compared to a detailed Collisional Radiative Model.
- OSTI ID:
- 22102343
- Journal Information:
- Journal of Applied Physics, Vol. 113, Issue 14; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Argon metastable density and temperature of a 94 GHz microplasma
Partial pressures of Zn and Se{sub 2} over ZnSe(c) from optical density measurements
Related Subjects
ABSORPTION
ARGON
ATOMS
BOLTZMANN EQUATION
DENSITY
DOPPLER BROADENING
ELECTRIC DISCHARGES
ELECTRON TEMPERATURE
EQUILIBRIUM
ION TEMPERATURE
LASER RADIATION
LASER SPECTROSCOPY
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA PRESSURE
RAYLEIGH SCATTERING
THOMSON SCATTERING
WAVELENGTHS