Generation regimes for the runaway-electron beam in gas

The generation of the runaway-electron beam in nitrogen and helium is studied at an oscillator voltage of about 25 kV. Various regimes of the electron beam generation with a pulse duration ranging from 200 ps to several nanoseconds are realized depending on the pressure in the gas diode. An ultrashort avalanche electron beam (UAEB) with a low (10–20%) variation in the voltage across the gap is obtained at a relatively high pressure in the gas diode. The UAEB generation can be delayed relative to the leading edge of the voltage pulse by tens of nanoseconds at low oscillator voltages.