Self-oscillations of positive corona current in nitrogen

Summary form only given. This paper reports on the conditions when the glow mode of a positive corona in nitrogen exists. For the first time, an auto-oscillating regime is observed. Detailed studies on characteristics of corona pulsation in an electrode system of wire (anode) and cylinder (cathode) were carried out. Waveforms for oscillations of current and glow intensity were measured. Voltage-current characteristics, amplitude and repetition frequency for oscillations were measured for a wide range of pressure (10-765 Torr). The repetition frequency of pulses varies in the range 200-500 MHz. Earlier discussed mechanisms for the development of oscillations are critically analyzed and a new one is proposed. A new interpretation of old measurements of preionized electron density in nitrogen and air produced by a positive corona is given. According to Morrow (1997), electrons in gas are produced by UV photons created in positive corona in a small region close to a pin. Direct measurements for these conditions performed by us evidenced that the positive corona generates soft X-rays which we refer to as the process of bremsstrahlung at the anode surface following collisions of fast electrons appearing in the close vicinity of the pin. We believe that these X-rays produced electrons in gas observed by Morrow (1997).