Mh. Gordon et Ch. Kruger, TEMPERATURE AND DENSITY-MEASUREMENTS IN A RECOMBINING ARGON PLASMA WITH DILUENT, Plasma chemistry and plasma processing, 13(3), 1993, pp. 365-378
Spectroscopic and calorimetric measurements of temperature and number
density have been made using a 50-kW radio-frequency inductively coupl
ed plasma (RFICP) torch operated at atmospheric pressure with maximum
temperatures and electron densities near 8,100 K and 2 x 10(21) m-3, r
espectively. These measurements enabled the determination of the state
of equilibrium and of the corresponding applicability of various diag
nostic techniques in both a recombining argon plasma and a recombining
plasma with hydrogen or nitrogen. Results indicate that the pure argo
n plasma is well described by a partial equilibrium model in which the
free and bound-excited electrons are in mutual equilibrium irrespecti
ve of possible departures from equilibrium with the ground state. The
addition of just tenths of a percent of either atomic hydrogen or nitr
ogen, however, disturbs this partial equilibrium in argon plasmas with
electron densities roughly less than 10(21) m-3 such that only diagno
stic techniques which are independent of partial equilibrium assumptio
ns can be reliably implemented