CHEMICAL REACTIONS IN ELECTRICAL DISCHARGES: III. THE POSITIVE COLUMN IN D-C. GLOW DISCHARGES THROUGH OXYGEN

Abstract

Discharges through fast-flowing oxygen have been investigated. It has been shown that the electrical field remains constant in the positive column of a particular mode, even in the presence of a large pressure gradient. It was found that five types of discharges could be distinguished and they can be characterized by fluctuations of the voltage at the electrodes. These oscillations are linked with the absence or presence of travelling waves in the column. The conditions of existence of the various discharges are outlined. It has also been shown that the structure of the positive column is not as homogeneous as previously thought. In particular, even at constant field, changes in the electron temperature and the number density of charged species are shown to occur. The change in electron temperature and the presence or absence of oscillations have been shown to affect the rate of production of atomic oxygen and the emission intensity of the spectrum of these discharges.