Effect of High-Voltage Electrode Potential Bias on the Breakdown Induced by Ionization Wave in Discharge Tube

An experimental study has been done of the bias effect of the active (high-voltage) electrode potential on the breakdown characteristics in a discharge tube 15 mm in diameter, filled with neon, argon, or their mixture (3 : 1) at a pressure of ~1 Torr. The bias of the potential is carried out by parallel connection to the electrode with an additional constant voltage or additional pulses with an amplitude less than the voltage for maintaining self-sustained discharge. In this case, a change in the breakdown voltage, the velocity of the pre-breakdown ionization wave, and the brightness of radiation from its front is observed. In particular, the breakdown voltage can increase up to 1.5–2 times, and this state of the discharge gap can be maintained for tens of minutes. The observed effects are assumed to be caused by the appearance of a charge on the tube wall and a change in its potential near the electrode, which affect the characteristics of the primary breakdown between the electrode and the wall and, in turn, the processes of discharge ignition. The mechanisms of appearance of the surface charge on the wall when feeding a bias voltage to electrode are investigated.