Mutual Effect of the Ionization Wave and the Surface Charge of the Wall During the Breakdown in the Discharge Tube

Abstract

The propagation of the ionization wave along the discharge tube with a precharged wall was studied. Pure inert gases, from neon to xenon, were used, as well as the Ne–Ar mixture, at pressures ~1 Torr. The discharge tubes had a length of 80 cm and a diameter of about 1.5 cm. The ionization wave was excited by a positive- or negative-polarity voltage pulse. The wall charge appeared as a result of the passage of the previous ionization wave initiated in the single-electrode mode. In this mode, the ionization wave is not accompanied by the ignition of the glow discharge. It was established that the time dependence of the longitudinal coordinate of the wave and its instantaneous velocity at each point were determined not by the exciting pulse amplitude but by its excess over the potential of the charged wall. This excess also determines the breakdown voltage in the tube with a precharged wall. This fact confirms the concept of the primary breakdown between the high-voltage electrode and the wall (Nedospasov and Novik, 1960) as the mechanism of the appearance of the ionization wave during the ignition of the glow discharge. Estimates of the characteristic lifetime of the wall charge were obtained.