共查询到18条相似文献,搜索用时 93 毫秒
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自由电子激光的空间电荷波理论 总被引:1,自引:0,他引:1
发展了相对论空间电荷波理论,并首先把空间电荷波理论用于建立自由电子激光的线性理论,揭示出自由电子激光中电子群聚及电子与波互作用机理的物理本质。并首次提出了“相对论去群聚”的物理概念,丰富了自由电子激光理论。同时提出了一些发展自由电子激光的新概念及新建议。 相似文献
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激光等离子体加速器能够在cm尺度内产生GeV量级的高品质电子束,为研制台式化自由电子激光提供驱动源。但是受限于激光等离子体加速中的难点和现有技术发展,电子束的品质难以达到自由电子激光的需求,尤其在稳定性、发散角和能散等方面,阻碍了台式化自由电子激光的研制。介绍了基于激光等离子体加速器的自由电子激光的最新进展,整理了目前高增益自由电子激光实验过程中存在的主要挑战和对应的解决方案与实验进展,并展望未来的发展方向。最近的研究结果证明,通过控制和优化激光等离子体加速器的注入和加速过程产生的高品质电子束可以在指数增益区域实现自发辐射放大,产生高增益的辐射,这也推动基于激光等离子体加速器的自由电子激光研究进入了一个新的阶段。 相似文献
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解析地研究了电子束的热效应对由基模群聚电子束产生的相干谐波功率的影响,并与外源预群聚电子束产生相干谐波的机制进行了比较.
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解析地研究了电子束在相对论速调管放大器(RKA)的调制腔和漂移管中的预群聚;第一次用粒子-波相互作用的场方法导出了在辐射腔中预群聚电子束产生辐射的自洽方程;并且计算了线性区的增益. 相似文献
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契伦柯夫自由电子激光可以产生远红外相干受激辐射。本文建立了契伦柯夫自由电子激光的动力学理论并详细研究了初始信号频率,电子束电压和束—介质膜间隙对器件性能的影响。与自由电子激光,回旋自谐振脉塞比较,指出了短波契伦柯夫自由电子激光的几个显著特点。 相似文献
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提出了一种过模复合器件。自洽地导出了由外电磁信号和预群聚电子束同时驱动的一种过模复合器件的辐射波相位锁定方程;讨论了到达锁相运行的时间、频率移动和带宽。分析表明:当由预群聚电子束和外电磁信号同时锁相时,通过调节参数,可以缩短到达锁相运行的时间,减小运行频率对要锁定的频率(外电磁信号频率)的移动和增大锁相运行的带宽。 相似文献
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Andreev N.E. Kuznetsov S.V. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(4):1170-1176
The theory of electron acceleration in a plasma wake wave is developed, and the dependence of the main characteristics of accelerated electron bunches on the wakefield parameters is investigated, It is shown that using a prebunching stage, under proper conditions, the final electron density of a compressed and accelerated bunch can exceed the initial electron beam density by orders of magnitude and that longitudinal bunch compression provides quasi-monoenergetic acceleration to high energies, It is demonstrated that, for an initial electron beam radius smaller than the optimal one for efficient beam trapping, the energy spread of the compressed and accelerated electron bunch and its length can be evaluated by using the simple analytical predictions of a one-dimensional (1-D) theory. The obtained analytical results are confirmed by three-dimensional (3-D) numerical modeling 相似文献
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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
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Manheimer W.M. Levush B. Antonsen T.M. Jr. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1990,18(3):350-368
Equilibria and stability (both single-mode and sideband) are calculated and contrasted for free-running, phase-locked, and mode-locked oscillator configurations in a quasi-optical gyrotron. The oscillator can be phase locked by direct injection of radiation into the oscillator cavity. The equilibrium and stability properties are not greatly affected at low injection power levels. Alternatively, the oscillator could be phase locked by prebunching the beam. If the beam is prebunched, there are dramatic effects on both equilibrium and stability. The transverse efficiency can be considerably enhanced by prebunching the beam. This prebunching can be done on either a phase-locked (using an external RF source) or mode-locked (using the oscillator output) configuration. The stable locking bandwidth turns out to be about half the ω/Q linewidth of the mode 相似文献
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Kong M.G. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1998,26(1):85-91
One important issue in waveguide free electron lasers (FELs) involves an interaction of the electron beam with one waveguide mode at two different resonant frequencies. Since the low-frequency mode often has a higher pain, the usually preferred high-frequency mode is suppressed as a result of mode competition. In this paper, possible control of this mode competition is considered using a nonstandard wiggler magnet consisting of two cascaded wiggler sections with different periods and field strengths. It is demonstrated that with an appropriate differentiation between the two wiggler sections the high-frequency mode may be amplified preferentially. This mode-selective amplification may be used to suppress the low-frequency mode. A small signal gain formulation is developed for a waveguide FEL with such a two-sectioned wiggler arrangement and numerical examples are used to demonstrate its applicability to mode control in waveguide FELs. Effects of wiggler field errors and electron energy spread are also considered. It is shown that the requirement for wiggler field errors and electron energy spread in the two-sectioned wiggler arrangement is similar to that in the usual straight wiggler configuration 相似文献
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assuming that the number of excited modes is large and their phases are random a quasi-linear theory of interaction of ultrarelativistic electron beam with the field of a high-quality cavity is developed. The saturation effects in FELs with an inhomogeneous frequency broadening are described. It is shown that in the case of very large excesses over threshold the efficiency of FELs tends to 50% but the emitted energy is distributed in a very wide spectral interval. 相似文献
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本文建立了圆极化摇摆场自由电子激光的单粒子理论,导出了电子未扰轨道及其稳定性判据和自由电子激光单程增益的表达式。单程增益由三项构成,其中第一项即自由电子激光不稳定性的增益与动力学理论得到的指数增益相符。第二项和和三项表明存在一对新的不稳定性——正不稳定性和负不稳定性。该理论没有对电子未扰轨道纵向速度作任何假设,不仅可以更合理地用于常规自由电子激光的研究,而且可以用于短周期摇摆器弱相对论自由电子激光研究。后者由于电子未扰轨道纵向速度比较低,已有的单粒子理论中所作的电子纵向速度约等于光速的假设不再成立。借助数值分析,我们发现:(1)稳定轨道Ⅱ的弱导引场区域也出现了动力学理论描述过的与自由电子激光互作用机理相悖的现象。(2)正不稳定性和负不稳定性在稳定轨道Ⅰ的导引磁场临界值附近可能严重影响自由电子激光的工作。(3)可以使用较弱的短周期摇摆场和较强的导引场产生高频率高增益相干受激辐射。 相似文献
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Linear accelerators delivering high brightness electron beams are essential for a number of current and proposed accelerator applications, such as free electron lasers (FELs). In this kind of facilities the charge density is high enough to drive collective effects (wakefields) that, notwithstanding the high beam rigidity at energies up to the GeV range, may increase the beam emittance relative to the injection level, eventually degrading the nominal beam brightness. New theoretical developments and experimental capabilities, driven by the recent construction of vacuum-ultra-violet and X-ray linac-driven FELs, have advanced the present knowledge. This article describes the progress in the field of ultra-relativistic electron beam manipulation to maximize the final beam brightness, with a focus on the most recent techniques including optics design, pulse shaping and brightness optimization strategies. The theoretical models are supported by a review of the experimental results in now-running FEL facilities. 相似文献