Generation of high-voltage pulses with subnanosecond front rise times in open discharge

Abstract

The investigation results for plasma switching devices of high-voltage pulses with pulse rise times less than 1 ns are presented. The approach is based on using conditions suitable for bringing a gas discharge chamber in a state with high conductivity due to generation of an electron beam owing to photoelectron emission from the device cathode. It is shown that in co-axial geometry pulses, switching time 0.45 ns on an active load RL = 50 Ω at voltage U = 20 kV can be achieved. It is shown with the method of doubled impulses that such a device can regenerate the acceptable electric strength during 10 μs. It is indicated of the principle possibility of working in the pulse-periodical regime to the repetition rate of 100 kHz.

Subnanosecond breakdown development in high-voltage pulse discharge: Effect of secondary electron emission

“…[9,15,16] the results of kinetic simulation of electron avalanche evolution for the experimental conditions [2,7] were presented. As was shown in [15], the secondary electron emission (SEE) becomes a dominant process in current growth at the final stage of breakdown.…”

“…The discharge operates between two paralel plane cathodes 6 mm apart and a mesh anode with 90% transparency placed in the middle between them. Applying high voltage leads to the generation of electron beam from the cathodes with the current density of 200÷400 A/cm 2 and current increase rate of 500 A/(cm 2 ns). Such type of discharges with unique parameters can be used as a source of electron beams or as subnanosecond high-power switches.…”

“…Recently the current exponential growth within a subnanosecond was registrated [2,7] during breakdown in high voltage open (HVO) discharges in helium. The discharge operates between two paralel plane cathodes 6 mm apart and a mesh anode with 90% transparency placed in the middle between them.…”

“…So the explalnation of subnanosecond breakdown development required understanding of specific physical procecces in HVO discharge plasma and complementation of existing physical model. In work [2] it was proposed that the key role in photoemission play the photons of resonant radiation, having Doppler shift. Such photons are radiated in processes of atomic excitation, involving fast atoms.…”

“…In the experiments with high-voltage open discharge in helium [1,2] a new method was proposed for switching of high power pulses with time less than a nanosecond. The high-voltage open discharge proved to be an useful tool for producing high-energy electron beams or subnanosecond high-power electrical switch.…”