Electronic Nonequilibrium in a Supersonic Expansion of Ionized Gas,
Abstract
An experimental and analytical study of nonequilibrium among the populations of the excited levels of electric arc heated potassium vapor injected in argon/helium gas flows passing through a Mach 2.2 supersonic nozzle is presented. Spectroscopic measurements (line intensity and line reversal) of the gas were performed upstream of the nozzle and at the nozzle exit. As the plasma proceeded through the nozzle the gas temperature dropped from 2500K to 1000K in 0.00003 seconds. The electron temperature also decreased rapidly, causing the free electrons to recombine with ions of potassium. The recombined electrons passing through the energy level structure of potassium formed the basis of the electronic nonequilibrium. A theory was written describing quantitatively the behavior of the excited atom populations. The electronics populations of expanded potassium vapor were observed to depart from equilibrium in qualitative accordance with the theoretical predictions. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1972
- Accession Number
- AD0750943
Entities
People
- Douglas David Mcgregor
Organizations
- Stanford University