Temperature time dependences in nitrogen pulse excited microwave discharge

Spectroscopic and microwave investigations were performed of a nitrogen discharge with the gas flowing through the discharge apparatus; the discharge was excited by a h.f. pulse. In such a discharge, currently used as a chemical plasma reactor, a marked non-equilibrium state exists of the electron, vibrational, rotational and translational temperatures. The conditions were found to be substantially affected by the duration of the h.f. pulse and by the gas pressure. Steady state was reached after a relaxation time of 10-4 sec. With h.f. pulses shorter than this relaxation time a plasma with a high electron temperature and high electron density could easily be achieved at relatively high pressures. (V.P.)