Peculiarities of plasma decay in the afterglow of a low-pressure pulsed discharge in oxygen

Weakly ionized plasma of a pulsed-discharge afterglow in oxygen at low pres sures (0.05-0.15 torr) is investigated using probe diagnostics. The plasma conductivity is measured by supplying an additional probing current pulse a t a certain instant during the afterglow. The spectral line intensities are also measured to additionally monitor the densities of charged particles. The measurements of the time behavior of the electron density in an oxygen afterglow plasma confirm the previous conclusion that the electrons escape due to enhanced diffusion, which results in the formation of an ion-ion pla sma. The possibility of realizing the opposite ultimate case-the detachment decay regime with an increase in the electron density to the density of po sitive ions in the first stage and the transition to the electron-ion plasm a in the second stage-is demonstrated. (C) 2001 MAIK "Nauka/ Interperiodica ".