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1.
An analyzer is created for time-resolved measurements of the electron pitch-angles in high-current microsecond relativistic electron beams in a strong magnetic field. The electron pitch-angles in a 500-keV relativistic electron beam with a current density of ∼1 kA/cm2 and a 1-μs flat-top current profile are measured. The diode proposed previously by the authors allows one to produce a high-current electron beam in which pitchangles vary only slightly with time and over the beam cross section. 相似文献
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Investigations of the generation and transport of a high-current, low-energy electron beam are performed in a system with
a gas-filled diode based on a plasma cathode. At accelerating voltages of up to 20 kV and pressures of (1–5)×10−1 Pa, a beam with an emission current of 600 A, emission current density of 12 A/cm2 and pulse duration of 30 μs if obtained in a diode with a grid-stabilized emission opening having a diameter equal to 8 cm.
The beam is transported in the absence of an external magnetic field over a distance of 20 cm. The beam is compressed by its
self-magnetic field, and the current density at the collector reaches 100 A/cm2 when the beam diameter is 3 cm.
Zh. Tekh. Fiz. 68, 44–48 (January 1998) 相似文献
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The problems of the formation of relativistic electron beams in a cylindrical diode with an annular cathode are discussed in the approximation of an infinitely strong guiding magnetic field. The beams are treated as infinitely thin. The following cases are investigated: 1) The formation of an electron beam moving off the cathode with an initial velocity. The case in which the field on the cathode is not equal to zero is investigated. It is shown that the potential of the electron beam can be determined in a nonunique fashion in the drift region. 2) The formation of a two-velocity electron beam. The possibility of controlling the flow of kinetic energy of the beam by varying the fraction of fast electrons in it is shown. 3) The formation of an electron beam in a diode with the help of two opposed cathodes at different potentials. A strong dependence of the current in the diode on the potential difference between the cathodes is obtained.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 36–39, December, 1981. 相似文献
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E. H. Baksht M. I. Lomaev D. V. Rybka D. A. Sorokin V. F. Tarasenko 《Technical Physics》2008,53(12):1560-1564
The parameters of an electron beam generated in helium in the pressure range p = 10−4−12 atm are studied. Nanosecond high-voltage pulses are applied to a gap between a tubular cathode and planar anode, which
is made of 45-μm-thick AlBe foil. Behind the anode, an electron beam is detected at a helium pressure of 12 atm. The pressure
dependence of the beam current amplitude shows three peaks at p ≈ 0.01, ≈ 0.07, and ≈ 3 atm. The beam-induced glow of a luminescent film placed behind the foil and the discharge glow at
different helium pressures in the gas-filled diode are photographed. 相似文献
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Goncharov A.A. Datsko N.I. Soloshenko I.A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1995,23(6):955-958
Based on state-of-the-art knowledge, the processes of the formation of intense ion beams in the transverse magnetic field of a commercial electromagnetic separator are analyzed. It is shown that, given the conditions of closed electron drift, the potentials will surely equalize along the fast ion trajectories all the way through the beam length; hence, no improvement in dynamic decompensation is caused by the low-frequency noise of the source. It is established that increasing the full beam current forces the maximum amplitude of the current density oscillations out to the beam periphery crosswise. For the first time, it is shown that suppressing noise oscillations in the arc discharge of an ion source for the formation of a highly stable ion beam with a minimum inner potential drop is possible. At low pressures, with collective interaction out of play, the drop is determined by Coulomb's collisions between the beam particles and compensating electrons. The analysis of collective phenomena likely to occur in the ion-beam plasma of a separator gives evidence of an experimental space potential buildup with increasing residual gas pressure in the calutron, leading to a high-frequency ion-electron beam instability. It is pointed out that this instability combined with an additional decompensation results in a noticeable broadening of the beam energy spectrum, which in turn makes for a lower quality of separation 相似文献
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Results are given for discharges in air and nitrogen near atmospheric pressure; the strength of the transverse magnetic field varies from 0 to 270 kOe. The results are explained in terms of the equivalent-pressure theory.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 69–74, May, 1973. 相似文献
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Effect of longitudinal applied magnetic field on the self-pinched critical current in intense electron beam diode 下载免费PDF全文
The effect of applied longitudinal magnetic field on the
self-pinched critical current in the intense electron beam diode is discussed.
The self-pinched critical current is derived and its validity is tested by
numerical simulations. The results shows that an applied longitudinal magnetic field
tends to increase the self-pinched critical current. Without the effect of
anode plasma, the maximal diode current approximately equals the
self-pinched critical current with the longitudinal magnetic field
applied; when self-pinched occurs, the diode current approaches the
self-pinched critical current. 相似文献
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The mechanisms behind limitation of current of nonrelativistic high-current electron beams in the plasma-filled diode immersed
in the external guiding magnetic field whose intensity is comparable with that of the beam self magnetic field are studied.
It is shown that the beam current is limited by transmission capacity of the double layer between the cathode and anode plasma
on the one hand and, on the other hand, by charge neutralization of the beam and by the decrease of the longitudinal velocity
of the beam electrons under the action of the induced electric field and of the beam self magnetic field. The effect of the
beam self fields on its cross-sectional current density and energy distributions is studied. Results of the numerical simulations
are in good agreement with the experimental data. 相似文献
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The field dependences of the transverse resistance of a single crystal of the layered superconductor Bi2Sr2CaCu2Oy (BSCCO-2212) with T
c
0≃92 K are studied in magnetic fields up to 50 T in the perpendicular orientation H⊥(ab). It is established that in the resistive region the resistance is a power-law function of the field, and the temperature
dependence of the barrier height for flux creep is obtained. It is found that in a wide temperature range, 50–125 K, the transverse
magnetoresistance of the crystal in the normal state and under conditions of superconductivity suppression by a strong magnetic
field is negative and can be approximated by a linear law with a temperature-dependent slope.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 5, 420–425 (10 September 1998) 相似文献
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Alexander Hramov Alexey Koronovskii Mikhail Morozov Alexander Mushtakov 《Physics letters. A》2008,372(6):876-883
In this Letter we research the space charge limiting current value at which the oscillating virtual cathode is formed in the relativistic electron beam as a function of the external magnetic field guiding the beam electrons. It is shown that the space charge limiting (critical) current decreases with growth of the external magnetic field, and that there is an optimal induction value of the magnetic field at which the critical current for the onset of virtual cathode oscillations in the electron beam is minimum. For the strong external magnetic field the space charge limiting current corresponds to the analytical relation derived under the assumption that the motion of the electron beam is one-dimensional [D.J. Sullivan, J.E. Walsh, E. Coutsias, in: V.L. Granatstein, I. Alexeff (Eds.), Virtual Cathode Oscillator (Vircator) Theory, in: High Power Microwave Sources, vol. 13, Artech House Microwave Library, 1987, Chapter 13]. Such behavior is explained by the characteristic features of the dynamics of electron space charge in the longitudinal and radial directions in the drift space at the different external magnetic fields. 相似文献
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The breakdown between coaxial cylindrical electrodes in the homogeneous axial magnetic field in the pressure range around the Paschen minimum is studied. On the right of this minimum the breakdown voltage is not practically influenced by a weak magnetic field. On the left of this minimum the breakdown U-B curves can be divided into two branches: the upper ones can be approximated by the magnetron cut-off parabola, the lower ones correspond qualitatively in some cases to the second solution of the equation for breakdown in the inhomogeneous electric field corrected with respect to the losses of electrons caused by recapturing on the cathode. 相似文献
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Hosokai T Kinoshita K Zhidkov A Maekawa A Yamazaki A Uesaka M 《Physical review letters》2006,97(7):075004
Significant enhancement of emittance and an increase of the total charge of femtosecond electron beams produced by a 12 TW, 40 fs laser pulse, tightly focused in a He gas jet, are observed after applying a static magnetic field, B> or =0.2 T, directed along the axis of laser pulse propagation. The effect appears when plasma produced by a laser prepulse becomes magnetized in the vicinity of the focus point: the electron Larmor frequency exceeds the collisional frequency, while periphery of the plasma remains unmagnetized. The entailed change in the shape of the plasma suppresses the diffraction of the main laser pulse that results in a much higher charge of electrons self-injected during the longitudinal wave breaking of the laser wake as well as the excellent stability of the beams. 相似文献
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We investigate tunneling decay in a magnetic field. Because of broken time-reversal symmetry, the standard WKB technique does not apply. The decay rate and the outcoming wave packet are found from the analysis of the set of the particle Hamiltonian trajectories and its singularities in complex space. The results are applied to tunneling from a strongly correlated 2D electron system in a magnetic field parallel to the layer. We show in a simple model that electron correlations strongly affect the tunneling rate. 相似文献