Numerical investigation of the parameters of a runaway electron beam generated in a gas-filled atmospheric-pressure hot-channel diode

Lisenkov, V. V.; Shklyaev, V. A.

doi:10.1134/s1063784214120160

Cited by 9 publications

(1 citation statement)

References 19 publications

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“…The dynamics of the electromagnetic field in a gas diode was calculated using the Maxwell equations system. Earlier, using a similar technique, a number of problems were solved for modeling the dynamics of the development of subnanosecond discharges developing with the participation of RAEs [87,91,92]. The modeling performed showed that the velocity of the IW motion sharply increases when moving through the gas ionized by RAEs.…”

Section: Factors Limiting the Pulse Breakdown Voltage At Hydrogen Pre...mentioning

confidence: 99%

Investigation of the switching characteristics of high-pressure subnanosecond gas dischargers with the purpose of a sharp increasing of the breakdown voltages and the switching speed

Ivanov¹

2022

Plasma Sources Sci. Technol.

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The paper analyzes the data obtained in the subnanosecond time range on the times (t br) and speeds (V br) of switching of hydrogen diode dischargers. These data were obtained in a wide range of hydrogen pressures (p) and the degree of the discharge gap overvoltage (the length of the cathode-anode gap d) in a uniform electric field. It is shown that the reduced strength of the average electric field E br/p in the discharge gap at the moment of the beginning of the breakdown significantly decreases when the gas pressure increases from 5 atm to 50 atm. An increase in pressure from 50 atm to 60 atm leads to a sharp (by 40–135%, depending on the d) increase in the pulse breakdown voltage (U br) and an increase in E br/p. In proportion to the growth of E br/p the switching speed V br of the discharge gas gap increases. The observed effect is explained by the change in the discharge initiation mechanisms. The limitation of U br and V br in the hydrogen pressure range from 5 atm to 50 atm occurs as a result of gas ionization by runaway electrons and the subsequent development of a multi-avalanche discharge in the volume of the discharge gap. With a further increase in pressure, the discharge develops according to the streamer type. To design ultrafast gas dischargers of the subnanosecond range intended for switching high voltages, it is necessary to select an appropriate range of working gas pressures in order to ensure the development of a streamer-type discharge.

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Section: Factors Limiting the Pulse Breakdown Voltage At Hydrogen Pre...mentioning

confidence: 99%

Investigation of the switching characteristics of high-pressure subnanosecond gas dischargers with the purpose of a sharp increasing of the breakdown voltages and the switching speed

Ivanov¹

2022

Plasma Sources Sci. Technol.

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Investigation of the prebreakdown stage of the self-sustained subnanosecond discharge in high pressure nitrogen

Ivanov

Lisenkov

2018

Journal of Applied Physics

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The results of the investigations of the prebreakdown stage of the self-sustained subnanosecond discharge in nitrogen at pressures between 5 and 40 atm are presented. A high voltage pulse with a front of approximately 250 ps at the level of 0.1–0.9 in amplitude (full duration of the pulse front was 500 ps) was applied to the studied gas gap. In this case, the voltage rise rate in the discharge gap at the prebreakdown stage reached up to 7 × 1014 V/s. Breakdown occurs at the front of the voltage pulse. During these experiments, the parameters of the voltage pulse at the output of the pulse generator were not modified. In this study, it was discovered that increasing of the pressure from 5 atm to 40 atm leads to a significant decrease in the overvoltage in the discharge gap. It is shown that at pressures above 10 atm, the delay time of breakdown is less than the time of growth for electron avalanches to reach a critical size. The critical length of avalanche is approximately one order of magnitude less than the length of the discharge gap. Hence, the avalanche-streamer model is inapplicable in this situation. A mechanism of subnanosecond breakdown initiation with a help of runaway electrons at pressures above 10 atm has been suggested.

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Investigation of the possibility of generation of runaway electrons in subnanosecond gas discharges of high and ultrahigh pressure in the vicinity of microprotrusions on the cathode surface

Ivanov,

Lisenkov

2024

Physics of Plasmas

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In the pressure range of 1–40 atm, experimental and theoretical studies of the processes of initiation and development dynamics of the initial stage of the self-sustained subnanosecond discharge in nitrogen, developing in a uniform electric field with the participation of runaway electrons, were carried out. Data on the maximum achievable values of the electric field strength in the discharge gap at the pre-breakdown stage of the discharge development and photographs of the microrelief of the surface of a stainless steel cathode formed during its training by subnanosecond high-voltage pulses were obtained. These data served as the basis for numerical 3D modeling of the development of an electron avalanche initiated by a field emission electron in a small region of enhanced electric field near a microinhomogeneity on the cathode. The possibility of transition of electrons in these avalanches to the runaway regime was studied. Cone-shaped microprotrusions, metal drops, and boundaries between pores and microcraters were considered as microinhomogeneities. It has been shown that the initial energy obtained by an electron near the microinhomogeneity can significantly facilitate its transfer into the runaway regime. This effect is especially noticeable at gas pressures higher 10 atm. As a result, at the stage of a self-sustained subnanosecond discharge formation, the runaway mode of an electron can be realized at the average reduced electric field strengths in the discharge gap, which are significantly lower than required by the runaway criterion.

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Numerical investigation of the parameters of a runaway electron beam generated in a gas-filled atmospheric-pressure hot-channel diode

Cited by 9 publications

References 19 publications

Investigation of the switching characteristics of high-pressure subnanosecond gas dischargers with the purpose of a sharp increasing of the breakdown voltages and the switching speed

Investigation of the switching characteristics of high-pressure subnanosecond gas dischargers with the purpose of a sharp increasing of the breakdown voltages and the switching speed

Investigation of the prebreakdown stage of the self-sustained subnanosecond discharge in high pressure nitrogen

Investigation of the possibility of generation of runaway electrons in subnanosecond gas discharges of high and ultrahigh pressure in the vicinity of microprotrusions on the cathode surface

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