ELECTRON TEMPERATURE AND NUMBER DENSITY MEASUREMENTS IN A NONEQUILIBRIUM PLASMA BOUNDARY LAYER.
STANFORD UNIV CALIF INST FOR PLASMA RESEARCH
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Measurements of the electron temperature and electron number density in a nonequilibrium plasma boundary layer are presented along with related analyses. The plasma consisted of atmospheric pressure NaK seeded argon at 2400 degrees K flowing over a cooled flat surface which was electrically floating and non-emitting. The analyses proceed from consideration of the coupled electron continuity and electron energy equations with boundary conditions appropriate to NaK seeded argon. The entire electron continuity equation is retained, including the ionization-recombination source term. Various source terms are included in the electron energy equation to account for elastic collisions, inelastic collisions with seed atoms, and inelastic collisions with gas additives such as molecular nitrogen. The equations are transformed into boundary layer coordinates using a local similarity transformation and are solved numerically for a range of plasma conditions. It is shown that the major nonequilibrium effects can be interpreted in terms of three characteristic lengths delta the thermal layer thickness, l sub E the characteristic length for electron energy exchange, and l sub I the characteristic length for ionization and recombination. Author
- Plasma Physics and Magnetohydrodynamics