共查询到20条相似文献,搜索用时 46 毫秒
1.
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
2.
Dynamics of an electron beam in a helical coaxial wiggler is studied. It is observed that the electrons perform betatron oscillation in a potential well that reflects the effective radiation pressure of the wiggler field and a centrifugal force due to an average azimuthal drift. 相似文献
3.
V. I. Vysotskii M. V. Vysotskii 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2008,2(2):253-263
Features of parametric effects during channeling of atomic ions, nuclei, and relativistic electrons (positrons) in crystals were considered. It was shown that parametric coupling between ion channeling states in the field of crystal axes and planes and electronic states in the ion volume leads to the possibility of “parametric collapse” of the beam, i.e., a decrease in the oscillation amplitude of the atomic ion in the channel due to periodic transfer of the ion oscillation energy to the inner electron of the atom. The same effect can be used to cool beams due to energy transfer to intrinsic nuclear states with low energy levels. It was shown that parametric cooling of beams with a decrease in the transverse energy can also occur during axial channeling of relativistic electron beams. This process results from the parametric coupling between channeling states, which are caused by the particle charge and electron spin states in an effective magnetic field induced in the moving coordinate system. 相似文献
4.
V. V. Ognivenko 《Journal of Experimental and Theoretical Physics》2012,115(5):938-946
The motion of the relativistic electron beam in the spatially periodic magnetic field of an undulator has been considered taking into account the effect of the incoherent field of the spontaneous undulator radiation on the motion of the electrons. An expression for the rms momentum of the electrons has been obtained. It has been shown that the momentum spread in the ultrarelativistic electron beam increases in the spontaneous incoherent emission mode. Conditions for the self-amplification of the spontaneous undulator radiation in ultrashort-wavelength free-electron lasers have been discussed. 相似文献
5.
V. V. Kashkovskii 《Russian Physics Journal》2005,48(10):1029-1038
Expressions for the vector potential and components of the magnetic field induction vector of a betatron with radial comb-type
poles are derived. The dynamics of the electron beam in the electromagnetic betatron field is investigated in the process
of electron injection and acceleration. It is demonstrated that the azimuthally varying field engender beam beats. However,
the amplitudes of beam particle oscillations during acceleration do not exceed their values estimated from the symmetric azimuthal
component of the betatron magnetic field induction. The energy spectrum of accelerated electrons is not described by a normal
law. In the electron energy spectrum, the relative number of electrons whose energy exceeds the average value is large. Application
of poles with radial combs improves the efficiency of electron capture in acceleration. Results of investigations can find
application in the development and adjustment of electron beam accelerating systems.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 27–34, October, 2005. 相似文献
6.
A. P. Yalovets 《Russian Physics Journal》1987,30(10):822-827
The effect of the self-field of an intense relativistic electron beam on its interaction with a dense medium was studied by solving a system of equations consisting of the kinetic equation for the fast electrons, the hydrodynamic equations for the plasma electrons, and Maxwell's equations for the electromagnetic field. It was assumed that the macroscopic parameters of the medium (its density, conductivity, and electron collision frequency) were independent of time. The system of equations was solved using high-order perturbation theory. The results show that a magnetic field is formed by the beam of fast electrons and to an equal degree by a current of thermalized electrons, which has not been taken into account before. It is shown also that the magnetic field of the beam affects its transmission through matter. In particular, the penetration depth of the electrons in matter and the transverse dimensions of the beam are both smaller than in a weak-current beam.Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 10, pp. 19–24, October, 1987.The author deeply thanks K. A. Dergobuzov for support of the work, and A. V. Arzhannikov, V. A. Klimenko, and A. V. Lapp for useful discussions. 相似文献
7.
《Physics letters. A》1988,129(7):386-389
The nonzero net dc force acting on relativistic beam electrons traveling in a uniform magnetic field, a laser wave, and transverse undulating magnetic field (magnetic wiggler) is calculated by using quantum-kinetics in accordance with the correspondence principle. It is found that the average of this force can be as strong as the Lorentz force of the laser wave in an electron energy region beyong energies for free electron lasing, and decreases linearly with the inverse of the electron energy far beyond this energy region. 相似文献
8.
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
9.
A possibility of precise measurement of the electron beam energy using absorption of radiation by electrons in a homogeneous magnetic field for electrons of high energy in the range up to a few hundred GeV, was considered earlier. In this paper, with the purpose of experimental checking of this method in the range of several tens MeV of electrons energies, a possibility of measurement of absolute energy of the electron beam with a relative accuracy up to 10?4, is considered. We take into account influence of the laser beam diffraction, of the spread of electrons over energies, and of the length of formation of radiation absorption in the process of electron beam energy measurement. The laser wavelength and the length of the magnet are chosen depending on the length of photon absorption formation. It is found that the kinematical restrictions on the photon absorption process lead to the selection in angles of propagation of photons, which can be absorbed by the beam electrons. It is shown that parameters of the electron beam will noticeably not vary during the measurement of the energy. 相似文献
10.
Relativistic electron motion in the electromagnetic Gaussian beam that propagates along a stationary magnetic field is studied.
It is shown that, if the cyclotron resonance conditions are initially satisfied, electrons can be efficiently accelerated
over a relatively small interval at a slightly lower rate than in a plane accelerating wave. 相似文献
11.
Boichenko A. M. Burachenko A. G. Kostyrya I. D. Tarasenko V. F. Tkachev A. N. 《Technical Physics》2011,56(8):1202-1209
The influence of the voltage pulse rise time on the amplitude of a runaway electron beam and X-ray generation in air and nitrogen
under atmospheric pressure is studied experimentally and theoretically. Generalization of the whistle criterion for the case
of a nonuniform field is suggested. It is shown that the maximal energy of beam electrons and the beam current amplitude grow
when the voltage pulse rise time decreases. It is found that the amplitude of the runaway electron current reaches a maximum
at a certain curvature of the cathode. The maximal energy of electrons increases when the radius of curvature of the cathode
exceeds the value at which the beam current amplitude is the highest. If the field is nonuniform, its critical value at which
many electrons run away is more than an order of magnitude lower than in the uniform field. 相似文献
12.
We present the results of numerical simulation and experimental studies of the systems of forming helical electron beams with
different topologies for a 1-MW gyrotron with step frequency tuning in the range 100–170 GHz. We analyze variations in the
beam parameters including the distribution of electrons over the oscillatory velocities, as functions of the beam current
for various accelerating voltages and magnetic fields. The results of experimental studies of a prototype of the multifrequency
gyrotron in the oscillation regime such that the designed optimized electron-optical system forms an intense helical electron
beam with specified parameters in a wide interval of magnetic fields are shown.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 9, pp. 773–784, September 2007. 相似文献
13.
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
14.
R. P. Fischer W. M. Manheimer A. W. Fliflet 《International Journal of Infrared and Millimeter Waves》1997,18(4):759-778
The linear theory used to design a two-resonator 85 GHz quasioptical gyroklystron with a nonuniform magnetic field is presented.
It is shown that a tapered magnetic field in the prebunching resonator has a relatively small effect on the electron bunching
parameter. The effect of velocity spread of the electron beam can be minimized by adjusting the magnetic field strength in
the two resonators. Measured amplifier performance is in good agreement with calculations from the nonlinear multimode simulation
code. Gyrophase bunching of the electrons is preserved over the long drift region (30 radiation wavelengths) even though no
attempt has been made to minimize the velocity spread of the beam. 相似文献
15.
《Physics letters. A》1988,127(1):52-56
The spectrum of magnetoplasma oscillations of a two-dimensional electron layer in a transversal magnetic field is studied under the condition that the electron system is unbounded along the layer plane and screened in the perpendicular direction. It is shown that under certain conditions oscillation frequencies much lower than the electron cyclotron frequency exist. Also the electromagnetic wave-guided oscillations in the system are described. It is shown that a strong magnetic field causes a frequency shift and splitting, depending inversely on the external magnetic field and the transversal specific dimension. 相似文献
16.
V. A. Fedorov 《Technical Physics》2007,52(4):483-488
The dynamics of self-consistent planar axisymmetric motions of a cylindrical electron beam is investigated analytically. The beam electrons move under the action of an unneutralized space-charge field against an immobile ion background or in a vacuum in the presence of a magnetic field. The electric field strength and the electron density and velocity are determined as functions of the distance traveled by the beam electrons. 相似文献
17.
H. Amemiya 《Physics letters. A》1977,63(2):103-104
It is shown experimentally that uenching by an external wave of a natural oscillation in the electron beam-plasma interaction of counter stream type occurs at discrete frequencies resonantly, where the velocity distribution function of beam electrons does not change substantially. 相似文献
18.
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
19.
Kwan T.J.T. Davis H.A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1988,16(2):185-191
The reflected-electrons discrimination microwave generator (reditron) is a high-power, narrow-band, and single-mode microwave generator that makes exclusive use of the oscillatory character of the virtual-cathode of a relativistic electron beam. The complex, nonlinear character of the virtual-cathode device necessitates particle-in-cell plasma simulation techniques. Investigations indicate two sources of the radiation: (1) the trapped electrons reflexing between the real and virtual cathodes, and (2) the oscillation of the virtual cathode. In the conventional design, the two mechanisms coexist and interfere with each other destructively, causing degradation of the efficiency of microwave generation. The authors have investigated a configuration with a slotted, thick anode and an external magnetic field, which effectively eliminates the reflexing electrons. Two-dimensional particle-in-cell simulations showed that such a configuration exploits the oscillation of the virtual cathode exclusively, and it generates single-mode, narrow bandwidth, and high-power microwave radiation with a potential efficiency over 10%. It was found that further optimization could be achieved by the use of a density (current) modulated electron beam at appropriate frequencies 相似文献
20.
HIRFL CSR的电子冷却系统是采用强流电子束对重离子束进行冷却。在冷却段漂移管区,由于强流电子束自身的空间电荷场和螺线管磁场的作用,使得电子束的包络发生振荡。通过求解电子束的横向包络方程,研究了强流电子束包络随电子束参数和螺线管聚焦磁场的变化关系。计算结果表明:对于不同的电子束能量和磁场,电子束包络的振荡频率也不相同;在相同的条件下,磁场越强,电子束包络振荡幅度越小,电子束能量越大,其包络的振荡频率也越快。 相似文献