Non-Local Thermodynamic Equilibrium in Laser-Sustained Plasmas

An argon laser sustained plasma (LSP) at atmospheric pressure has been studied spectroscopically and the existence of a non-local thermodynamic state has been determined. The spectroscopic data consist of several argon neutral and ion line emissions used to spatially resolve electronic energy level population densities in each plasma species. A hydrogen seed in added to the argon flow for the purpose of determining electron number density by Stark broadening analysis of the Balmer series alpha line. Neutral and ionic argon electronic excitation temperatures are calculated from the spectroscopic data. Electron and heavy particle kinetic temperatures are calculated through the use of an appropriate nonequilibrium model which includes multitemperature gas state, and ionization equations. The dominant nonequilibrium effect in this plasma is kinetic nonequilibrium where the electron kinetic temperature can be more than twice the heavy particle kinetic temperature in high laser power flux regions. Typical electron and heavy particle kinetic temperatures are 14000 K and 8000 K, respectively. Electron number density ranges from 6 $\times$ 10$\sp{22}$ m$\sp{-3}$ to 2.1 $\times$ 10$\sp{23}$ m$\sp{-3}$.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

1992

Author dc:creator

• Zerkle, David Karl

Contributors dc:contributor

• Krier, Herman

• Engineering, Mechanical
• Physics, Fluid and Plasma

Identifier

(UMI)AAI9305748

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/72234