X-ray diagnostics of runaway electrons generated during nanosecond discharge in gas at elevated pressures

Yatom, Shurik; Levko, Dmitry; Gleizer, J. Z.; Vekselman, V.; Krasik, Ya. E.

doi:10.1063/1.3675462

Cited by 19 publications

(7 citation statements)

References 12 publications

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“…X-ray radiation was detected at pulse repetition frequencies of 3 [44] and 1 [106] kHz. The energy of runaway electrons was determined from the energy of x-ray quanta [107]. However, since hundreds of papers are devoted to the study of x-ray radiation, we did not set the task to analyze these papers in this review.…”

Section: Saeb Energy Distributionmentioning

confidence: 99%

Runaway electrons in diffuse gas discharges

Тарасенко

2020

Plasma Sources Sci. Technol.

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The paper provides a review of research data showing the role of runaway electrons in gas breakdowns and diffuse discharges in an inhomogeneous electric field at a pressure of 0.01-1.2 MPa. From the data presented the reader can grasp the idea of how such discharges develop at negative and at positive voltage polarity, what setups and conditions are best suited to detect runaway electron beams, and what factors influence their amplitude, duration, and energy. Also analyzed are the streamer mechanisms of diffuse discharges and the generation of runaway electrons in high-pressure gases in an inhomogeneous electric field. The review is supplemented with respective diagrams and with images captured at high resolution to trace the plasma dynamics of nanosecond gas discharges from early prebreakdown stages till their final diffuse appearance.

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Section: Saeb Energy Distributionmentioning

confidence: 99%

Runaway electrons in diffuse gas discharges

Тарасенко

2020

Plasma Sources Sci. Technol.

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“…For example, the super-short avalanche electron beams in air and nitrogen were observed in [27] by using a small-curvature radius cathode and a flat anode. A powerful x-ray emission was recorded behind a thin-foil anode during high-voltage breakdown in atmospheric-pressure air and other gases [28][29][30][31]. The energetic electrons, observed in the experiments, lead to the formation of diffuse discharges.…”

Section: Diffuse Dischargesmentioning

confidence: 99%

Formation of wide negative streamers in air and helium: the role of fast electrons

Babaeva¹,

Naidis²,

Терешонок³

et al. 2022

J. Phys. D: Appl. Phys.

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Available experimental data show that the use of voltage pulses with subnanosecond rise times and amplitudes that essentially exceed the breakdown voltage leads to the formation of wide spherical or conical streamers. In this paper, the structure and dynamics of atmospheric pressure wide negative streamers in air and helium by applying high overvoltages with a short rise time to a sharp needle electrode are investigated experimentally and computationally. In the simulations, the two-dimensional fluid and kinetic Electron Monte Carlo Simulation models are used. All the streamers were simulated with the conventional photoionization term Sph that was never turned off. By including an additional source SMC, responsible for the generation of fast electrons, wide and diffuse streamers are obtained. We compare the shapes, width and velocities of conventional streamers in air and helium with those for streamers driven by fast electrons. We show that a conventional streamer in air has a cylindrical form. The conventional streamer in helium is wider than that in air and has a shape of an expanding cone. While accounting for fast electrons, different streamer shapes were obtained. In air, the gap was closed by a spherical streamer. In helium, the shape of a streamer resembles that of a pumpkin. By the application of high (by a factor of four or greater) overvoltages to a sharp needle electrode, the formation of a discharge with several parallel streamers was observed. In this regime, the trajectories of fast electrons originated not only from the cathode, but also from the region of a streamer front where the electric field is high. As a result, the so-called diffuse discharge was formed with high intensity plasma channels surrounded by an aureole of smaller electron density.

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“…In the case of ns-timescale discharge between the stainless steel blade cathode (~5 µm thick and 10 mm in length) and anode placed at the distance 1-4 cm, the diode was supplied by negative polarity HV pulses with a full width at half maximum (FWHM) duration of ~1 and ~5 ns and an amplitude ⩽150 kV, produced by an all-solid-state generator based on magnetically compression stages and semiconductor opening switches [7][8][9][10][11][12][13][14]. In order to avoid voltage reflections, an oil-filled transmission coaxial line (100 Ω impedance) was used between the generator and the diode.…”

Section: Experimental Setup and Diagnosticsmentioning

confidence: 99%

Recent studies on nanosecond-timescale pressurized gas discharges

Yatom

Shlapakovski

Beilin

et al. 2016

Plasma Sources Sci. Technol.

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The results of recent experimental and numerical studies of nanosecond high-voltage discharges in pressurized gases are reviewed. The discharges were ignited in a diode filled by different gases within a wide range of pressures by an applied pulsed voltage or by a laser pulse in the gas-filled charged resonant microwave cavity. Fast-framing imaging of light emission, optical emission spectroscopy, x-ray foil spectrometry and coherent anti-Stokes Raman scattering were used to study temporal and spatial evolution of the discharge plasma density and temperature, energy distribution function of runaway electrons and dynamics of the electric field in the plasma channel. The results obtained allow a deeper understanding of discharge dynamical properties in the nanosecond timescale, which is important for various applications of these types of discharges in pressurized gases.

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X-ray diagnostics of runaway electrons generated during nanosecond discharge in gas at elevated pressures

Cited by 19 publications

References 12 publications

Runaway electrons in diffuse gas discharges

Runaway electrons in diffuse gas discharges

Formation of wide negative streamers in air and helium: the role of fast electrons

Recent studies on nanosecond-timescale pressurized gas discharges

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