共查询到20条相似文献,搜索用时 15 毫秒
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We describe mechanisms of microwave pulse shortening in radiation sources with the power of about 108 W based on interaction between relativistic electron beams of nanosecond duration and preformed plasma. The shortening is mainly due to the electron return flow through the plasma, which leads to a multiple decrease in the linear gain of the microwave by the relativistic electron beam and in the reflection coefficient of the plasma wave that provides the generator feedback. The ways to eliminate the effect of microwave pulse shortening are proposed. 相似文献
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A. P. Yalovets 《Russian Physics Journal》1979,22(9):979-984
A solution is presented for the problem of passage of a high-current relativistic electron beam through matter in the stationary case with one-dimensional geometry. The system of equations describing the passage of the beam consists of the kinetic equation for fast electrons, which considers the effect of the electric field on the magnitude and direction of particle momentum, the equations for the field produced by the space charge generated by thermalized electrons, and relations connecting the conductivity of the medium to the radiation field. Higher-order perturbation theory is used for the solution. The solutions reveal that the distribution of expended energy, thermalized electrons, and other properties of the flow are highly dependent on the density of the incident flux and the conductivity of the medium. It will be shown that linear transfer theory may be applied to calculation of the passage of high-current beams through matter over a wide range of currents and conductivities, if the barrier thickness does not exceed one-half the path length, but cannot be used for calculation of passage through large-thickness barriers, i.e., with thickness comparable to the electron free path length.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 67–74, September, 1979.The author thanks A. N. Didenko and A. M. Kol'chuzhkin for their evaluation of the study. 相似文献
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The nonlinear stage in the development of a resistive hose instability of a highcurrent relativistic electron beam in a finite-conductivity plasma has been studied in the rigid-beam model. The attenuation of the force of the interaction of the beam with the magnetic field of the total current for large beam displacements is shown to result in the stabilization of the instability. The stabilization time and the amplitudes of the oscillations in the saturation regime are determined as functions of the parameters of the beam in the plasma.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fiz., No. 10, pp. 78–81, October, 1987. 相似文献
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E. F. Dudarev G. P. Pochivalova D. I. Proskurovskii V. P. Rotshtein A. B. Markov 《Russian Physics Journal》1996,39(3):284-288
A technique for determination of residual stresses at various distances from the irradiated surface is proposed. It is established for iron and molybdenum that compressive stresses are set up under irradiation by low-energy high-current electron beams and that their values decrease sharply with increasing distance from the surface. The residual stresses are much smaller in absolute magnitude than those operating during irradiation. It is shown that the change in resistance to microplastic deformation on irradiation with low-energy high-current electron beams is governed not only by formation of a gradient dislocation substructure in the surface layer, but also by the residual stresses and the appearance of the Bauschinger effect.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 126–132, March, 1996. 相似文献
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Stability conditions of high-current thin beams of relativistic electrons against excitation of long-wave oscillations in a stellatron and modified betatron have been investigated theoretically. The influence of self electric and magnetic fields obtained from electron beam delayed potentials has been taken into consideration. The correspondent dispersion relation has been found. The electron beam of the modified betatron has been shown to be always unstable against excitation of the oscillations considered. Necessary and sufficient conditions for the elec-tron beam confinement in a stellatron have been found. 相似文献
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M. L. Petrosyan B. V. Petrosyan G. M. Petrosyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2007,42(5):204-208
The experimental study of excitation of wake-field waves in plasma by a sequence of electron bunches of a microtron beam has been carried out. Results of measurement of the spectrum of electrons after their passage through plasma confirm the effect of adding of waves from a sequence of about 100 bunches which leads to the increase in the amplitude from 1 V/cm up to 100 V/cm. 相似文献
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A. B. Markov S. A. Kitsanov V. P. Rotshtein S. D. Polenin D. I. Proskurovskii E. F. Dudarev 《Russian Physics Journal》2006,49(7):758-765
This paper presents the results of investigations of the dynamic spall fracture of bulk (2–6 mm) copper targets under the
action of a relativistic high-current electron beam (1.3 MeV electron energy, 50 ns pulse duration, ∼1010 W/cm2 power density) generated by the SINUS-7 accelerator. By numerical simulation with the use of the BETAIN1 software package
it has been found that the amplitude of the stress wave formed is 6 GPa and the deformation rate is 5·105 s−1. As established experimentally, there is a practically linear relationship between the thickness of the target and the thickness
of the spalled layer. Comparison of the experimental data and the simulation results has shown that the spall strength of
copper under the given conditions is 1.3 GPa, which is in good agreement with the data available in the literature. Analysis
performed with the use of fractographic teqniques has revealed that in the case of recrystallized copper the size of the spall
pits formed inside the grains is four times greater than the size of the pits formed on the grain boundaries.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 69–74, July, 2006. 相似文献
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Kinetic theory of the plasma-dynamical modes and the transport coefficients of a relativistic plasma
The kinetic equation of an inhomogeneous relativistic plasma, consisting of an electron gas and a radiation field, is studied with particular regard to its eigenvalues in the hydrodynamical limit. The treatment is classical for the particles and quantum-mechanical for the field oscillators.After a suitable regularization, the eigenvalues are obtained by a perturbation theory through second order in the strength of the gradients. It is shown that these eigenvalues are in exact correspondence with the macroscopic relativistic plasma-dynamical modes. The important role played by the Vlassov operator in building up the peculiar structure of these modes is underlined. From a comparison of the macroscopic and microscopic eigenvalues we obtain general expressions for the thermal conductivity, the shear viscosity and the bulk viscosity of a relativistic plasma. The contribution of the radiation field to these quantities is a noteworthy feature of these expressions. 相似文献