Study of the Formation Time of a Self-Sustained Subnanosecond Discharge at High and Ultrahigh Gas Pressures

Ivanov, S. N.; Lisenkov, V. V.

doi:10.1134/s1063780x18030042

Cited by 8 publications

(22 citation statements)

References 18 publications

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“…The second important parameter of any spark gap is the pulse breakdown voltage (U br ). In general in the subnanosecond range [22][23][24][25][26][27][28][29] and as observed in the experiments [27][28][29] analyzed in this study, breakdown occurs at the front of the voltage pulse applied to the gas discharge gap (figure 1). Obviously, a number of technological and research tasks may require dischargers with the highest possible U br .…”

Section: Introductionsupporting

confidence: 68%

“…High voltage pulse (figure 3) with a front of about 250 ps at the level of 0.1 ÷ 0.9 in amplitude and a half-height duration of 400 ps was applied to the studied hydrogen gap. The pulse parameters coincided with the parameters of the pulse applied to the discharge gas gap in my experiments on the registration of RAEs at nitrogen pressures up to 40 atm [28,[67][68][69] and on the study of the switching characteristics of nitrogen [25][26][27]. This makes it possible to correctly compare the results of experiments on subnanosecond breakdown in various gases and to reveal the common regularities of the discharge development for them.…”

Section: Experimental Setup and Resultsmentioning

confidence: 59%

“…At higher pressures, the electrical breakdown of the gap will occur before we reach the value E cr /p required by the runaway criterion, since E cr increases proportionally to p [30,47]. Therefore, when analyzing the prebreakdown stage at gas pressures above 3 atm, the avalanche-streamer model of the discharge development was usually used [23][24][25][26]66].…”

Section: Introductionmentioning

confidence: 99%

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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: Introductionsupporting

confidence: 68%

Section: Experimental Setup and Resultsmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

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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 Lyman band intensity increases with decreasing H 2 pressure, and its maximum is observed at a pressure of 15-35 Torr. This is due to an increase in the overvoltage across the gap during the diffuse discharge formation by nanosecond high-voltages pulses when H 2 pressure is decreased [32,33]. Consequently, the Е/p parameter across the discharge gap increases, which improves the population rate of the B 1 Σ + u level of the H 2 molecule.…”

Section: Hydrogen Lasermentioning

confidence: 99%

VUV lasing in diffuse discharges formed by runaway electrons

Panchenko,

Tarasenko,

Kozevnikov

2023

Laser Phys.

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The parameters of stimulated emission in diffuse discharges formed in a sharply inhomogeneous electric field by runaway electrons in mixtures of rare gases with the addition of H2 and F2 at pressures up to 10 atm are studied. Efficient VUV lasing was obtained at wavelengths from 148 to 193 nm on the transitions of H2, F2 and exciplex ArF* molecules. It was shown that the addition of He buffer gas increases the pulse duration, while Ne addition improves the output energy of the VUV laser on the H2 Lyman band. A laser pulse duration over 10 ns and an output of 0.12 mJ were obtained. The diffuse discharge in mixtures of He with F2 was found to form as a result of successive ionization waves. It was shown that the laser pulse at 157 nm has three peaks, which correspond to the maxima of the diffuse discharge current. Therewith, the first or second peak of the laser radiation has the maximum intensity, depending on the amplitude of the conduction current in the primary ionization wave. A maximal F2* laser electrical efficiency of η 0 = 0.18% and an output of Q 157 = 3.8 mJ were obtained in a He–F2 gas mixture at pressure of 10 atm, which exceeds the efficiency of lasers of this type pumped by transverse volume discharges with UV preionization. Long-pulse operation of the ArF* laser was achieved in a He–Ne–Ar–F2 gas mixture. Lasing at 193 nm continued during two periods of the diffuse discharge current. The total duration of the laser pulse was as long as 40 ns, and the radiation energy at 193 nm was as high as 2 mJ from an active volume of 20 cm3.

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“…Подробное описание данной модели приведено в работах[17,23]. 1D расчеты формирования объемного разряда с предварительной ионизацией газовой среды были проведены ранее в[15] для смеси CO 2 : N 2 : He с давлением 1 atm применительно к экспериментальным условиям[24,25], и в[17] для N 2 с давлением 4 atm применительно к условиям[26][27][28][29]. В настоящей работе исследование будет проводиться на примере азота при давлении 1 atm.…”

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Численное Исследование Возможности Генерации Убегающих Электронов В Формирующемся Катодном Слое Самостоятельного Объемного Разряда Высокого Давления

Лисенков¹

2020

Журнал Технической Физики

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Calculations of the formation of the cathode layer of an self-sustained high-pressure volume discharge with pre-ionization of the gas medium excited by nano-and subnanosecond voltage pulses are carried out. It is shown that at pressures of ~ 1 atm at the final stage of the cathode layer formation, conditions for the generation of escaping electrons arise. We also considered the transition of electrons into runaway mode from the area of electric field amplification in front of the plasma (streamer) channel, which originates from the top of the micro-spike on the cathode. It is shown that at pressures of ~ 10 atm, electrons can transfer into runaway mode immediately after emission from the top of micro-spike in amplified electric field. Thus obtained runaway electrons can create pre-ionization of the gaseous medium and provide the formation of the initial phase of the discharge in volume form in the system without external pre-ionization.

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Study of the Formation Time of a Self-Sustained Subnanosecond Discharge at High and Ultrahigh Gas Pressures

Cited by 8 publications

References 18 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

VUV lasing in diffuse discharges formed by runaway electrons

Численное Исследование Возможности Генерации Убегающих Электронов В Формирующемся Катодном Слое Самостоятельного Объемного Разряда Высокого Давления

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