Abstract
Glow discharges have been used in gas lasers and the plasma processing. However, it is difficult to sustain a stable glow discharge at a high input electric power. One of methods to sustain the stable glow discharges is to use the gas flow. The phenomena of glow discharges in the gas flow are not understood clearly.
In this paper, the characteristics of glow discharge for a point-to-plane gap in the gas flow are investigated. The point electrode is the hemispherically ended electrode of 0.5mm in radius, and the gap length is 10mm in the nitrogen of several hundred Torr. The light emission from the glow discharge in the gas flow seems to spread, and waveforms of the current and voltage are oscillatory. It is found from the detail measurements of the discharge that the gas flow prevents to sustain the stable glow discharge and produces discharges which repeat the glow discharge and the discharge just before the transition to the glow discharge. In the positive point-to-plane gap, the discharge current just before the transition to the glow discharge is pulsative. In the negative point-to-plane gap, the discharge current is pulseless. The difference of the discharge just before the transition to the glow discharge in one of reasons why characteristics of the discharge in the gas flow change by the polarity.
