Level populations in plasmas RF discharges and sonic channel

Abstract

An absolute intensity calibration has been made to previously reported spectrographic measurements in an extensively studied argon rf discharge downstream of the exciting coil, and sonic afterglow. This calibration allows calculation of neutral argon atom density and of individual level population. Neutral atom densities were calculated from the electron density, the electron temperature, and Saha's equation, assuming that the electron temperatures were equal to the excitation temperatures. The densities calculated by these methods were far higher than those obtained from the perfect gas law, the gas temperature, and the pressure. The observed under- population of the ground level is shown to correspond to the “terminal non-equilibrium” defined by PARK. (3) The present data are compared with two existing experiments to show that agreement exists among seemingly inconsistent and confusing reports, provided the non-equilibrium phenomena are properly accounted for.