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Properties of runaway electron beams and x-ray radiation in a nanosecond volume discharge in air at atmospheric pressure are
investigated, and results of recent studies in this direction are analyzed. A physical nature of forming runaway electron
beams and x-ray radiation in the nanosecond volume discharge is discussed.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 40–51, December, 2005. 相似文献
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V. F. Tarasenko E. Kh. Baksht A. G. Burachenko I. D. Kostyrya M. I. Lomaev D. V. Rybka 《Technical Physics》2010,55(2):210-218
High-pressure nanosecond diffuse (volume) discharges in a nonuniform electric field are studied experimentally using a recording system with a ?100-ps time resolution. As the voltage pulse shrinks to a width of ≈100 ps, the initiation of a diffuse discharge without a source of additional ionization is facilitated; specifically, a runaway-electron-preionized diffuse discharge is ignited in atmospheric-pressure air in the case of short interelectrode gaps. It is found that a major energy deposit into the plasma of this discharge is from an abnormal glow discharge following a maximum of the gap voltage. 相似文献
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E. H. Baksht A. G. Burachenko M. V. Erofeev I. D. Kostyrya M. I. Lomaev D. V. Rybka V. F. Tarasenko 《Technical Physics》2008,53(6):804-807
The effect of a transverse magnetic field (0.080 and 0.016 T) on generation of an electron beam in the gas-filled diode is
experimentally investigated. It is shown that, at voltage U = 25 kV across the diode and a low helium pressure (45 Torr), the transverse magnetic field influences the beam current amplitude
behind a foil and its distribution over the foil cross section. At elevated pressures and under the conditions of ultrashort
avalanche electron beam formation in helium, nitrogen, and air, the transverse magnetic field (0.080 and 0.016 T) has a minor
effect on the amplitude and duration of the beam behind the foil. It is established that, when the voltage of the pulse generator
reaches several hundreds of kilovolts, some runaway electrons (including the electrons from the discharge plasma near the
cathode) are incident on the side walls of the diode. 相似文献
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E. H. Baksht A. G. Burachenko A. V. Kozyrev I. D. Kostyrya M. I. Lomaev V. K. Petin D. V. Rybka V. F. Tarasenko S. V. Shljakhtun 《Technical Physics》2009,54(1):47-55
The spectra of electrons and X-ray photons generated in nanosecond discharges in air under atmospheric pressure are investigated
theoretically and experimentally. Data for the discharge formation dynamics in a nonuniform electric field are gathered. It
is confirmed that voltage pulses with an amplitude of more than 100 kV and a rise time of 1 ns or less causing breakdown of
an electrode gap with a small-radius cathode generate runaway electrons, which can be divided into three groups in energy
(their energy varies from several kiloelectronvolts to several hundreds of kiloelectronvolts). It is also borne out that the
formation of the space charge is due to electrons appearing in the gap at the cathode and a major contribution to the electron
beam behind the foil comes from electrons of the second group, the maximal energy of which roughly corresponds to the voltage
across the gap during electron beam generation. X-ray radiation from the gas-filled diode results from beam electron slowdown
both in the anode and in the gap. It is shown that the amount of group-3 electrons with an energy above the energy gained
by runaway electrons (in the absence of losses) at a maximal voltage across the gap is much smaller than the amount of group-2
electrons. 相似文献
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S. B. Alekseev E. Kh. Baksht A. M. Boichenko I. D. Kostyrya V. F. Tarasenko A. N. Tkachev 《Technical Physics》2012,57(9):1192-1198
The dependences of the electron beam intensity and X-ray dose on the thickness of metal foils (Al, Cu) in a nanosecond discharge initiated in atmospheric-pressure air are studied theoretically and experimentally. Calculated curves of electron beam attenuation in aluminum and X-ray dose attenuation in copper agree well with experimental data. It is found that the amplitude of a super-short avalanche electron beam and the X-ray exposure dose reach maximal values at different values of the interelectrode gap. When the length of the cathode??s edge with a small radius of curvature increases, an interelectrode gap maximizing the amplitude of the runaway electron current shrinks. 相似文献
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The properties of the discharge in and radiation from an open gas-filled diode to which high-voltage nanosecond pulses are applied from the RADAN-220 generator are studied. Electromagnetic radiation in the X-ray, UV, visible, and near-IR ranges of the spectrum, as well as high-power subnanosecond (0.5-to 0.7-ns-long) pulses of ultra-wide-band (UWB) electromagnetic radiation, are recorded when a diffuse discharge is initiated in atmospheric pressure air. For the coaxial cathode and anode, the open gas diode emits radially polarized UWB pulses, whereas for the cathode in the form of a segment, the UWB radiation is linearly polarized. The effective potential for both designs of the diode is ER = 6 kV. It is shown that the plasma in the discharge gap serves as a source of soft X rays and the metallic anode generates hard X rays. 相似文献
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V. B. Bratchikov K. A. Gagarinov I. D. Kostyrya V. F. Tarasenko A. N. Tkachev S. I. Yakovlenko 《Technical Physics》2007,52(7):856-864
X-ray radiation from the volume discharge in atmospheric-pressure air is studied under the conditions when the voltage pulse rise time varies from 0.5 to 100 ns and the open-circuit voltage amplitude of the generator varies from 20 to 750 kV. It is shown that a volume discharge from a needle-like cathode forms at a relatively wide voltage pulse (to ≈60 ns in this work). The volume character of the discharge is due to preionization by fast electrons, which arise when the electric field concentrates at the cathode and in the discharge gap. As the voltage pulse rise time grows, X-ray radiation comes largely from the discharge gap in accordance with previous experiments. Propagation of fast avalanche electrons in nitrogen subjected to a nonuniform unsteady electric field is simulated. It is demonstrated that the amount of hard X-ray photons grows not only with increasing voltage amplitude but also with shortening pulse rise time. 相似文献
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I. D. Kostyrya V. M. Orlovskiĭ V. F. Tarasenko A. N. Tkachev S. I. Yakovlenko 《Technical Physics》2005,50(7):881-885
A study is made of the formation of a volume discharge in atmospheric-pressure air in a nonuniform electric field without additional preionization. It is shown that the spatial distribution of the plasma glow between a plane and a spherical (as well as a point) electrode at a subnanosecond rise time of the high-voltage pulse is volumetric in character. The change of the voltage polarity does not qualitatively affect the character of the glow. The propagation of a spherical ionization wave in nitrogen is calculated in the drift-diffusion approximation. The fact that the character of the discharge glow is essentially independent of the voltage polarity is explained by the multiplication of the background electrons in the dense working gas. 相似文献