On physical processes in an ‘open’ discharge

This paper reviews the key features of the ‘open’ photoelectric discharge (FED) used for the high-efficiency generation of electron beams (EBs) in medium-pressure gases and for subnanosecond switching of high-voltage pulses. The energy efficiency of EB generation in both FEDs and anomalous discharges is measured, and conditions for the predominance of photoemission are formulated. It is concluded that the FED is a long-known phenomenon and that the arguments put forward in Usp. Fiz. Nauk 188 1354 (2018) [Physics–Uspekhi 61 1234 (12) (2018)] against its existence are based on simplified discharge models and poorly performed experiments and make use of other authors' results of no direct relevance to the ‘open’ discharge.