Study of the switching rate of gas-discharge devices based on the open discharge with counter-propagating electron beams

Abstract

The switching rate of gas-discharge devices “kivotrons” based on the open discharge with counter-propagating electron beams has been experimentally studied. Structures with 2-cm2 overall cathode area were examined. The switching time was found to show a monotonic decrease with increasing the working-gas helium pressure and with increasing the voltage across the discharge gap at breakdown. The minimum switching time was found to be ∼240 ps at 17 kV voltage, and the maximum rate of electric-current rise limited by the discharge-circuit inductance was 3 × 1012 A/s.

Operating characteristics of open discharge-based plasma switches with helium, nitrogen and oxygen

“…Thus, in open discharge devices with counter propagating electron beams generation, in helium [6][7][8][9][10][11][12], etc but also in mixtures of helium with molecular gases-nitrogen or oxygen as well as in pure molecular gases, fast switching devices of nanosecond and subnanosecond range are realizable. Even at moderate voltage U ∼ 10 kV, the switching efficiency in all cases exceeds 80%.…”

“…They are used for fast switching of high voltage pulses, generation of vacuum ultraviolet (VUV) and x-ray radiation, forming of high intensity electron beams, pumping of gas and solid-state lasers and other applications [1][2][3][4][5][6]. This class of devices also includes recently developed open discharge switching devices [7][8][9][10][11][12]. Their use makes it possible to improve the output characteristics of a number of devices and facility, in particular, copper vapor lasers [13], to generate high-frequency oscillations with a frequency of several GHz and the duration of a few pulses [8], etc.…”

“…extended drift space. A structure with two oppositely spaced discharge gaps and consequently counter propagating electron beams being generated in the discharge can function as a voltage sharper-a kivotron [7][8][9]11] with the number of commutated pulses up to at least 10 11 [6,9,14,15]. Fast switching, up to a switching time of ∼80-100 ps, is provided mainly by photoemission under the influence of resonant VUV radiation from fast helium atoms, having a large Doppler shift relative to the line center, and at the final stage of current development, due to secondary electron emission [16], which determine the long lifetime of the devices.…”

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

“…The pulse shape is registrated with the low-inductive resistive divider with the rate about 20:1 using oscilloscope Tektronix DPO 70804C with a bandwidth of 8 GHz. The registration circuit and other experimental conditions were described in details in [1]. In the experiments three types of cathodes made from different materials were tested.…”

“…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.…”