Accession Number : AD0602714

Title :   SPECTROSCOPY OF A SUPERSONIC PLASMA. I. EXCITATION MECHANISM,

Corporate Author : ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AIR FORCE STATION TENN

Personal Author(s) : Brewer,LeRoy E.

Report Date : JUL 1964

Pagination or Media Count : 18

Abstract : Spectral line emission has been shown to be strongly influenced by the existence of metastable states in plasmas. The distribution function for excited electronic states in a plasma in which an excess over equilibrium density of metastable atoms is present is derived by the establishment of a suitable model. This is accomplished by considering two different atoms which are identical except for their ground states. A Boltzmann distribution function is written for each type of atom for the upper energy states, and the two distributions are summed to obtain the population of the nth state due to both the normal and metastable atoms. Argon was used as an example for calculations which show that the population of a given excited state may be several orders of magnitude greater than that which would be expected if metastable atoms were not present. When including this new term in the Einstein-Boltzmann spectral line intensity equation, it is seen that intensities are considerably altered when even a slight excess concentration of metastable atoms is present. Experimental evidence in support of the form of the equation is presented. (Author)

Descriptors :   (*PLASMA JETS, SPECTROSCOPY), SUPERSONIC FLOW, PLASMAS(PHYSICS), ATOMS, ATOMIC ENERGY LEVELS, EXCITATION, ARGON, STATISTICAL FUNCTIONS, LINE SPECTRA, EQUATIONS

Distribution Statement : APPROVED FOR PUBLIC RELEASE