We present time resolved spectroscopic measurements of 1064 nm laser produced plasma in air at pressures from 0.85 to 48.3 bar. This paper reports on the measurement of temperature and electron number density of the plasmas at times between 100 ns and 3000 ns from the plasma onset. Neutral atomic oxygen lines at 715 nm and 777 nm are used for temperature measurement through a Boltzmann analysis. Electron number density is measured using Stark broadened atomic hydrogen (Hα) line at 656 nm. We employ Taylor-Sedov blast wave theory to calculate initial plasma pressures and utilize thermo-chemical computations of the plasma to determine plasma compositions. Both ideal and non-ideal behaviors of the plasma are considered. In the former case, plasma composition is computed by minimizing the specific Gibbs free energy and solving the system of nonlinear coupled equilibrium equations. The non-ideal behaviour is taken into account by considering Coulomb interactions between charged particles within the framework of the Debye-Hückel model. © 2010 by the American Institute of Aeronautics and Astronautics, Inc.
A Time Resolved Spectroscopic Study of Laser Generated Plasmas in Air at High Pressures
D'ANGOLA, Antonio;
2010-01-01
Abstract
We present time resolved spectroscopic measurements of 1064 nm laser produced plasma in air at pressures from 0.85 to 48.3 bar. This paper reports on the measurement of temperature and electron number density of the plasmas at times between 100 ns and 3000 ns from the plasma onset. Neutral atomic oxygen lines at 715 nm and 777 nm are used for temperature measurement through a Boltzmann analysis. Electron number density is measured using Stark broadened atomic hydrogen (Hα) line at 656 nm. We employ Taylor-Sedov blast wave theory to calculate initial plasma pressures and utilize thermo-chemical computations of the plasma to determine plasma compositions. Both ideal and non-ideal behaviors of the plasma are considered. In the former case, plasma composition is computed by minimizing the specific Gibbs free energy and solving the system of nonlinear coupled equilibrium equations. The non-ideal behaviour is taken into account by considering Coulomb interactions between charged particles within the framework of the Debye-Hückel model. © 2010 by the American Institute of Aeronautics and Astronautics, Inc.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
