Efficient oscillation regimes of an HF laser pumped by a nonchain chemical reaction initiated by a self-sustained discharge

New insight is provided into how runaway electrons are generated in gases. It is shown that the Townsend mechanism of electron multiplication works even for strong fields, when the ionization friction of electrons can be neglected. The nonlocal electron runaway criterion proposed in the work determines the critical voltage ± pd relationship as a two-valued function universal for a given gas (p being the gas pressure, and d the electrode spacing). This relationship exhibits an additional upper branch as contrasted to the familiar Paschen's curves and divides the discharge gap into two regions: one where electrons multiply effectively, and the other which they leave without having enough time to multiply. Experiments on the production of electron beams with subnanosecond pulse duration and an amplitude of tens to hundreds of amperes at atmospheric pressure in various gases are addressed, and the creation of a nanosecond volume discharge with the high density of excitation power and without preionization of the gap by a supplementary source is discussed.

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“…6). In their experiments, Panchenko et al [48] found that at Eap % 117 V cm À1 Torr À1 volume discharge in SF 6 also ceases to develop.…”

Section: September 2004mentioning

confidence: 95%

The electron runaway mechanism in dense gases and the production of high-power subnanosecond electron beams

Тарасенко¹,

Yakovlenko²

2004

Phys.-Usp.

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147

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“…Diffuse discharge in the system of blade electrodes, similarly to a volume discharge in non‐chain chemical lasers with profiled electrodes [18, 19], can cease until the generator capacity is completely discharged. In this case, a repeated breakdown of the gap in the form of a spark is possible.…”

Section: Resultsmentioning

confidence: 99%

Diffuse discharges in SF ₆ and mixtures of SF ₆ with H ₂ , formed by nanosecond voltage pulses in non‐uniform electric field

et al. 2018

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Results of experimental study of nanosecond diffuse discharge in SF 6 and gas mixtures of SF 6 with H 2 , D 2 and C 2 H 6 are presented. The aim of this work is to study parameters of discharge between two extended electrodes with a small radius of curvature in SF 6 and SF 6 with additives. It was shown that diffuse discharge can be formed in SF 6 at elevated pressure between blade electrodes with length of 30 cm. It was also confirmed that in a sharply non-uniform electric field a beam of runaway electrons is generated and that the gap breakdown occurs due to ionisation waves which begin on electrodes with small radius of curvature. Laser action in the infrared spectral region was obtained in SF 6-H 2 (D 2 , C 2 H 6) mixtures. The laser output up to 110 mJ was easily achieved which corresponds to ultimate intrinsic efficiency (with respect to deposited energy) of 10%.

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“…Therewith up to 85% of the laser output is emitted in the cascades ending on the most intensive lines of P 1 band. The number of HF laser lines increases with E in and can be as high as 30 with C 0 =70 nF 13 . The laser spectra are very similar to those obtained with the e-beam initiation providing uniform energy deposition into the laser active media 15,16 .…”

Section: Radiation Spectramentioning

confidence: 99%

“…Discharge initiated HF(DF) laser was similar to the set-up excited by the inductive or LC-generators and described in details in 13 . The discharge gap d=3,8 cm between two polished special shaped stainless steel electrodes 70 cm in length, providing uniform electric field in the active volume, was preionised by 72 spark gaps evenly distributed along both sides of the anode.…”

Section: Experimental Technique and Measurement Proceduresmentioning

confidence: 99%

“…Earlier we have demonstrated that discharge stabilization allows to improve the laser intrinsic efficiency η int (relative to deposited energy) and η int =10% in wide range of the pumping pulse parameters was obtained 13 . In the present report, pumping pulse parameters providing ultimate efficiency of discharge non-chain HF-and DF-lasers are found and processes affecting the laser efficiency are discussed.…”

Section: Introductionmentioning

confidence: 97%

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Efficient nonchain discharge HF and DF lasers

Панченко

Orlovskiĭ

Тарасенко

2004

High-Power Laser Ablation V

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Discharge and laser parameters in mixtures of SF 6 with H 2 and D 2 are studied using inductive and LC-generators. Excitation pulse parameters providing ultimate performance of discharge non-chain HF-and DF-lasers are determined.Processes affecting efficiency of the lasers are discussed. Ultimate intrinsic efficiency η int of the HF and DF lasers up to 10 % and 7%, respectively, was realized in the SF 6 -H 2 (D 2 ) mixtures. Electrical efficiency of the lasers up to η 0 =5-6% with the output over 1 J was demonstrated for the first time.

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Efficient oscillation regimes of an HF laser pumped by a nonchain chemical reaction initiated by a self-sustained discharge

Cited by 12 publications

References 18 publications

The electron runaway mechanism in dense gases and the production of high-power subnanosecond electron beams

The electron runaway mechanism in dense gases and the production of high-power subnanosecond electron beams

Diffuse discharges in SF ₆ and mixtures of SF ₆ with H ₂ , formed by nanosecond voltage pulses in non‐uniform electric field

Efficient nonchain discharge HF and DF lasers

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Efficient oscillation regimes of an HF laser pumped by a nonchain chemical reaction initiated by a self-sustained discharge

Cited by 12 publications

References 18 publications

The electron runaway mechanism in dense gases and the production of high-power subnanosecond electron beams

The electron runaway mechanism in dense gases and the production of high-power subnanosecond electron beams

Diffuse discharges in SF 6 and mixtures of SF 6 with H 2 , formed by nanosecond voltage pulses in non‐uniform electric field

Efficient nonchain discharge HF and DF lasers

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Product

Resources

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Diffuse discharges in SF ₆ and mixtures of SF ₆ with H ₂ , formed by nanosecond voltage pulses in non‐uniform electric field