A Collisional-Radiative Model and Saha Decrements for a Nonequilibrium Oxygen Plasma
Abstract
When air is heated and becomes highly ionized, the primary constituents cnsist of nitrogen, oxygen and their ions. Emissions from this plasma provide diagnostic information as well as contribute to cooling the plasma. To describe such a plasma under nonequilibrium conditions one must known the population densities of various excited states. Using a time dependent approach a collisional-radiative model is developed for an oxygen plasma. Effective recombination and ionization coefficients are calculated for two specific cases, optically thin and optically thick in bound-bound UV radiation. The steady state population densities for neutral and ionic states are presented in terms of their deviations from Saha equilibrium predictions. These results show the approach of the plasma to a state of local thermodynamic equilibrium (LTE) as a function of electron temperatures between 1.0 and 3.0 eV and electron densities between 10 to the 16th power and 10 to the 19th power/cc.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 20, 1986
- Accession Number
- ADA168082
Entities
People
- A. W. Ali
- Ronald D. Taylor
Organizations
- United States Naval Research Laboratory