ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Optical absorption spectroscopy has been applied to measure the absolute population densities of the first excited levels of atomic hydrogen H*(n=2) and argon Ar*(4s) in an expanding cascaded arc plasma in hydrogen-argon mixture. It is demonstrated that the method allows us to determine both H*(n=2) and Ar*(4s) absolute density radial profiles for H2 admixtures in Ar ranging from 0.7% to 10% with good accuracy. The measured H*(n=2) densities are in the 1014–1016 m−3 range, and Ar*(4s) densities are in the range of 1015–1018 m−3. It has been shown, that the density of hydrogen excited atoms H*(n=2) serves as an indicator of the presence of argon ions and hydrogen molecules in the expanding plasma. A kinetic model is used to understand evolution of H*(n=2) density in the expansion, and to estimate the total atomic hydrogen population density and hydrogen dissociation degree in sub- and supersonic regions of the plasma.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.357281
