RELAXATION TO THE STEADY STATE IN A CONDUCTING NONEQUILIBRIUM PLASMA STREAM
ARO INC ARNOLD AFS TN
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The relaxation of a seeded plasma subjected to a constant electric field is considered within the formalism of the two-temperature theory. Numerical solutions are obtained for streamwise conductivity profiles in both argon and nitrogen plasmas seeded with potassium. Reaction rates used here are analytical formulae based on the Byron model for collision-induced recombination. Extensive analysis of the computed results and comparison with Zukoskis experiments in argon establish the validity of the basic treatment and suggest the existence of energy losses resulting from excitation of argon transitions originating at the first excited state, in addition to the usual elastic collision and potassium excitation energy losses. Details of the Byron model are validated by comparison of theoretical and experimental time-resolved potassium emission lines. Possible nonequilibrium effects in nitrogen are investigated with various assumed molecular excitation losses. Relaxation times for both types of plasmas are correlated by use of Zukoskis characteristic time parameter.
- Plasma Physics and Magnetohydrodynamics