共查询到20条相似文献,搜索用时 31 毫秒
1.
N. S. Ginzburg V. Yu. Zaslavskii I. V. Zotova A. M. Malkin N. Yu. Peskov A. S. Sergeev 《JETP Letters》2010,91(6):266-270
The possibility of creating high-power tunable planar terahertz free-electron lasers based on modified Bragg structures with
the coupling of paraxial and transverse (with respect to the velocity of particles) wave fluxes has been demonstrated. In
addition to the compatibility with the transport channels of intense electron beams, the advantage of the proposed structures
is the spatial coherence of radiation at a large oversize factor of the interaction region in two transverse coordinates. 相似文献
2.
The use of incoherent multiwave pump radiation or randomly varying magnetostatic fields (stochastic undulators) for improving
the energy conversion efficiency in free-electron lasers based on stimulated wave scattering and the stimulated undulator
emission of relativistic electron beams is proposed. It is shown within the quasilinear approximation that the electronic
efficiency increases in proportion to the width of the pump spectrum due to enrichment of the spectrum of combination waves
which are synchronous with the electron beam and realization of a mechanism of stochastic particle deceleration when the signal
wave is monochromatic. At the same time, the efficiency scarcely depends on the spread of the beam parameters, making the
use of the method promising for improving the efficiency of free-electron lasers powered by intense relativistic electron
beams.
Zh. Tekh. Fiz. 67, 77–81 (July 1997) 相似文献
3.
The effect of dispersion on the lasing of waveguide free-electron lasers driven by short periodic electron bunches is considered. In the high-Q cavity approximation, the generation of electromagnetic pulses is described in terms of a parabolic equation. For the linear stage of interaction, starting lasing conditions are found analytically and the spatio-temporal structure of supermodes, which represent a set of phase-locked eigenmodes of the cold cavity, is determined. Dispersion is shown to allow the free-electron laser to operate at both positive and negative mismatches between the period of electron bunch injection and the time taken for the electromagnetic pulse to circulate over the cavity. The simulation of the nonlinear lasing conditions with allowance for dispersion spread makes it possible to find the stationary profile of radiated pulses and the optimum values of the group and time detunings that provide a maximum efficiency of the waveguide free-electron laser. It is also shown that, when the length of interaction is much longer than the starting value, the laser operates under the conditions of periodic or chaotic pulse profile self-modulation. 相似文献
4.
采用单电子模型和经典辐射理论分别对低能和高能电子在线偏振激光驻波场中的运动和辐射过程进行了研究. 结果表明: 垂直于激光电场方向入射的低速电子在激光驻波场中随着光强的增大, 逐渐从一维近周期运动演变为二维折叠运动, 并产生强的微米量级波长的太赫兹辐射; 高能电子垂直或者平行于激光电场方向入射到激光驻波场中, 都会产生波长在几个纳米的高频辐射; 低能电子与激光驻波场作用中, 激光强度影响着电子的运动形式、辐射频率以及辐射强度; 高能电子入射时, 激光强度影响了电子高频辐射的强度, 电子初始能量影响着辐射的频率; 电子能量越高, 产生的辐射频率越大. 研究表明可以由激光加速电子的方式得到不同能量的电子束, 并利用电子束在激光驻波场的辐射使之成为太赫兹和X射线波段的小型辐射源. 研究结果可以为实验研究和利用激光驻波场中的电子辐射提供依据. 相似文献
5.
Arbel M Abramovich A Eichenbaum AL Gover A Kleinman H Pinhasi Y Yakover IM 《Physical review letters》2001,86(12):2561-2564
An electron beam, prebunched at the synchronous free-electron laser frequency and passing through a magnetic undulator, emits coherent (superradiant) synchrotron undulator radiation at the bunching frequency. If an external electromagnetic wave is introduced into the interaction region, at the same frequency and at a proper phase, the radiation process will be stimulated (stimulated prebunched beam radiation). We report first experimental measurements of stimulated superradiant emission in a prebunched free-electron maser. Measurements are in good agreement with theory. 相似文献
6.
A. Gover 《Applied Physics A: Materials Science & Processing》1980,23(3):295-298
An analysis of stimulated emission of radiation by an electron beam passing through a periodic longitudinal electrostatic
field is presented, and its use in a free-electron laser structure is discussed. The analysis is based on a coupled-mode calculation
of the interaction between a waveguided electromagnetic mode and an electron-beam plasma with finite cross section. The dispersion
equation derived applies to the collective as well as the single electron regime.
This research is supported in part by AFOSR Grant, 77-3445. 相似文献
7.
We predict that coherent electromagnetic radiation in the 1-100 THz frequency range can be generated in crystalline materials when subject to a shock wave or soliton-like propagating excitation. To our knowledge, this phenomenon represents a fundamentally new form of coherent optical radiation source that is distinct from lasers and free-electron lasers. The radiation is generated by the synchronized motion of large numbers of atoms when a shock wave propagates through a crystal. General analytical theory and NaCl molecular dynamics simulations demonstrate coherence lengths on the order of mm (around 20 THz) and potentially greater. The emission frequencies are determined by the shock speed and the lattice constants of the crystal and can potentially be used to determine atomic-scale properties of the shocked material. 相似文献
8.
The effect of high-current relativistic electron beams (REB's) on the undulator field amplitude in free-electron lasers (FEL's) is investigated. Two mechanisms of excitation of periodic magnetostatic self-fields by REB are considered: 1) a static mechanism that is realized at stationary motion of REB in the undulator field; and 2) a dynamic mechanism that is realized at signal wave amplification. The static mechanism in the absence of an axial magnetic field leads to a decrease of the total undulator field amplitude (a diamagnetic effect). The dynamic mechanism for low-density beams leads to an increase of the total undulator field amplitude (a paramagnetic effect), with a subsequent increase of electron efficiency. For high-density beams, the effect of the phase shift of the total undulator field is most essential, due to which the growth of the signal wave amplitude is limited by nonlinear mismatch of synchronism. 相似文献
9.
A method is proposed for conditioning electron beams via Thomson scattering. The conditioning provides a quadratic correlation between the electron energy deviation and the betatron amplitude of the electrons, which results in enhanced gain in free-electron lasers. Quantum effects imply conditioning must occur at high laser fluence and moderate electron energy. Conditioning of x-ray free-electron lasers should be achievable with present laser technology, leading to significant size and cost reductions of these large-scale facilities. 相似文献
10.
E. M. Belenov S. V. Grigor'ev A. V. Nazarkin I. V. Smetanin 《Journal of Russian Laser Research》1990,11(5):498-503
The coherent interaction of an electromagnetic field with the medium in those cases in which the current emission in matter can be described within the framework of the two-level quantum system is considered. The physical nature of such cases is quite different. The media may be two-level particles (atoms or molecules), superconducting planar structures (e.g., high-temperature superconductors, HTSC, or relativistic electron beams in a free-electron laser (FEL). Also, the dynamics of the electromagnetic field for the visible, microwave, and x-ray wavelength region can be described. A short review of the results is given in the section on two-level particle media. The results of studying the interaction of the field with the electron beams in an x-ray FEL and the field interaction with the HTSC medium are the first to be reported.Translated from Preprint No. 82, Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow, 1990. 相似文献
11.
A 2D nonstationary model of induced emission of ribbon-shaped electron beams and clusters in free space is developed in the
quasi-optical approximation. On the basis of this model, the problem of enhancement of a short electromagnetic pulse propagating
along a quasi-stationary ribbon electron flow, the theory of a BWT-type oscillator with radiation channeling by an electron
beam, and the process of collective acceleration of a short electron cluster in the field of an intense cocurrent wave are
considered. 相似文献
12.
The interaction of an electron beam, moving inside a magnetic lattice, with an electromagnetic wave is considered. It is shown that under certain conditions generation (amplification) of coherent electromagnetic radiation occurs. The gain is calculated. 相似文献
13.
14.
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
15.
A theory of free-electron lasers fed a sequence of short electron pulses is developed. It is assumed that the group velocity
of the electromagnetic pulse that develops in the cavity is the same as the translational velocity of the particles, and the
repetition period of the electron pulses equals the transit time of the electromagnetic radiation in the cavity. Under these
conditions of group synchronism, the principal factors governing the feasibility of establishing a stationary pulsed lasing
regime are found to be the dispersive spread of the electromagnetic pulse and the channeling properties of an electron bunch.
The conditions for self-excitation are found, and the characteristics of the stationary lasing regimes are determined assuming
that the cavity has a high Q and using a parabolic equation for the evolution of the electromagnetic pulse shape.
Zh. Tekh. Fiz. 69, 78–83 (February 1999) 相似文献
16.
The nonlinear dynamics of coaxial free-electron masers with 2D distributed feedback, which is realizable in 2D Bragg structures,
is analyzed in terms of a quasi-optical approximation. It is shown that feedback with the spatial synchronization of radiations
from tubular electron beams with a perimeter exceeding 1000 wavelengths can be provided under such conditions. The objects
of investigation are the one-section design of a free-electron maser with 2D distributed feedback and a design with a combined
two-mirror resonator. In the latter, an entrance 2D Bragg mirror provides the spatial synchronization of radiation and weak
reflections from a conventional exit Bragg mirror are sufficient for the self-excitation of the oscillator. The advantage
of the two-mirror design is a decrease in ohmic losses. The adequacy of the geometric optics approximation used earlier to
describe the dynamics of such self-excited oscillators is demonstrated under various boundary conditions for transverse (azimuthal)
energy fluxes at the edges of a Bragg structure. 相似文献
17.
Ginzburg N. S. Kocharovskaya E. R. Sergeev A. S. Fil’chenkov S. E. 《JETP Letters》2021,113(10):626-630
JETP Letters - A quasilinear theory is developed for free-electron lasers in which intense electron beams with a significant velocity dispersion are used to implement the kinetic regime of... 相似文献
18.
Terahertz radiation from carbon nanorings in external collinear constant and varying electric fields
We consider the response of a quasi-one-dimensional ballistic carbon ring to the field of an electromagnetic wave propagating along the normal to the ring plane in the presence of a constant electric field collinear to the field of the wave. The dipole moment and the radiation intensity of the ring are calculated for the ballistic motion of a conduction electron. The possibility of implementation of regular periodic and chaotic regimes of ring emission under the action of external fields is demonstrated. The radiation spectrum of the ring is analyzed, and the dependence of the scattering cross section for an electromagnetic wave incident on the ring on its frequency and amplitude is calculated. 相似文献
19.
N. S. Ginzburg V. Yu. Zaslavskii A. M. Malkin A. S. Sergeev 《Technical Physics》2012,57(12):1692-1705
A nonlinear nonstationary theory of surface-wave oscillators with 1D and 2D periodic structures is constructed in terms of a quasi-optical approach. The radiation field is represented as a superposition of quasi-optical wave beams coupled on a corrugated surface and forming a self-consistent structure. Synchronous interaction with rectilinear relativistic ribbon and cylindrical electron beams is observed when the surface wave slows down. The results obtained in terms of the average approach are compared with those obtained by direct numerical particle-in-cell simulation. The feasibility of creating small-size millimeterwave gigawatt power supplies based on 2D planar and cylindrical surface-wave oscillators is demonstrated. 相似文献
20.
The interaction of free electrons and free electromagnetic radiation, in the presence of a uniform magnetic field, can result
in stimulated emission or absorption. We analyze the dynamics of single electrons by solving the classical, relativistic Lorentz
force equations of motion in these combined fields. An electron may gain energy from, or lose energy to, the radiation field,
depending crucially on the phase and oscillation frequency of the electron's helical motion within the superposed, circularly
polarized light wave. To first order in the radiation field strength, electrons in a monoenergetic, uniformly distributed
beam become spatially bunched, but there is no net energy change. To second order, however, the beam may experience a gain
or loss of energy, corresponding to attenuation or amplification of radiation. We compare the bunching of this laser process
to the bunching processes involved in 1) the Stanford free-electron laser and 2) the cyclotron maser, and find significant
differences in each case. Our analytic results provide a clear, simple picture of the interaction process, and can be useful
in exploring light amplification in astrophysical magnetic fields, the magnetosphere, or in laboratory devices.
Supported in part by Army Contract No. DASG 60-77-C-0083 and NASA Grant NSG-7490. 相似文献