The existence of two forms of unipolar gas-breakdown discharge

The existence of two forms of unipolar gas-breakdown discharge that depend on the pulse-repetition frequency and the polarity of high-voltage pulses is experimentally revealed. These two forms differ in their intensities, the distribution of luminescence on the discharge length, and their volt-ampere characteristics. The transition from one discharge form to another proceeds in a narrow frequency range and is caused by the breakdown of the near-electrode layer in some critical field under the inclusion of ion-electron emission process. The transition frequency increases with the growth of the gas pressure and a decrease of the pulse amplitude. The development of discharge instability and the hysteresis of its parameters are observed in the transition area.