相对论空间电荷波理论

本文研究了相对论电子注中的空间电荷波,建立了相对论空间电荷波的一般理论。导出了空间电荷波方程,定义了相对论动电压,并探讨了它的物理含义;导出了相对论电子注的动功率流定律,求得了相对论空间电荷波的正规模式。     

电真空器件

0210526相对论行波管色散特性分析〔刊〕/谢鸿全//强激光与粒子束.-2002,14(1).-11l～114(K) 数值计算了一种填充等离子体的波纹波导结构的行波管,在强引导磁场下,被一环形相对论电子注驱动的小信号增益。详细地分析了等离子体的浓度、电子注的电压、电流及其在慢波结构中的传输位置对行波管的增益、带宽和中心频率的影响。参12     

大功率毫米波环板行波管注波互作用线性理论研究

考虑了电子注的厚度和相对效应，采和场匹配和变分法中的特殊方法－－Ritz-Galerkin法，导出了考虑电子束空间电荷效应的环板行波管的热然散方程，并对该方程进行数值求解，得到了其小讯号增益，讨论了慢波系统几何尺寸和电子注参量对小信号增益的影响，为毫米波环板行波管的设计提供了理论依据。     

环形相对论电子注激励的等离子体介质切伦可夫脉塞

利用自洽线性场理论，考虑电子的三维扰动，分析了环形相对论电子注在填充背景等离子体的介质筒慢波波导产生的切伦可夫辐射，其环形电子注对主波互作用的作用完全要用一跳变条件来描述，导出了其色散方程和波波互作用的同步条件，求得了是子注产生的波增长率，分析了背景等离子体密度和电子注半径对波增长率的影响。     

实心注在等离子体介质筒产生的切伦可夫辐射

利用自洽线性场理论：考虑电子的三维扰动，分析了轴向实心相对论电子注通过填充背景等离子体介质筒慢波波导产生的切伦可夫辐射，导出了描述其不稳定性的色散方程和注液互作用的同步条件，求得出电磁波辐射的时间增长率，分析了背景等离子体密度和实心电子注半径对波增长率的影响。     

相对论返波振荡器的非线性理论

本文建立起分析相对论返波管注波互作用过程的自洽非线性工作方程组,理论模型中计及了正向波基波与电子注的异步互作用效应、电子注的空间电荷效应.运用四阶龙格一库塔法编制了数值求解工作方程组的Fortran程序,对均匀耦合阻抗型器件和耦合阻抗单阶跃变型器件的效率进行了仿真和优化.数值模拟结果表明正向波基波与同步波在慢波结构起始处的相差,正向波基波与电子注的异步互作用效应能显著地影响相对论返波管效率,均匀阻抗器件运行于最佳状态时,效率可达到27%,耦合阻抗单阶跃变型器件最优化效率可达到50%.     

无引导磁场电子注的空间电荷波

本文导出了无外磁场电子注在等离子体约束下其上传播的空间电荷波波动方程,详细讨论了该条件下的波特性,并对等离子体频率降低因子进行了分析．研究表明,等离子体填充状况对空间电荷波性质影响甚大,选择等离子体填充因子可对空间电荷波性质进行适当的控制．     

S波段耦合腔行波管非线性注-波互作用方程组的数值解

推导了考虑相对论效应的一维非线性注-波互作用自洽工作方程组.借鉴田炳耕的圆盘模型推导空间电荷场.对空间电荷场表达式提出简化假设并使其归一化,该假设将大大节省考虑空间电荷场时的计算时间.编写计算机程序对注-波互作用自洽工作方程组进行了数值求解,利用该程序分析了空间电荷力对注-波互作用的影响,得出S波段耦合腔行渡管的效率,增益和瞬时带宽.计算结果表明:在2.87～3.35 GHz频带范围内效率达到14%以上,增益大于18.5 dB,瞬时带宽达到15%,结果达到设计要求.     

磁化环形等离子体填充波导中注-波互作用的研究

该文利用线性理论,对相对论环形电子注与环形等离子体互作用产生微波辐射进行了研究。在考虑有限磁场的基础上,利用匹配场法求得色散方程。重点分析了等离子体密度、厚度,外加磁场对等离子体切伦可夫脉塞注-波互作用的影响,并计算了各参量变化时的波增长率以及色散关系。     

无引导磁场电子流的空间电荷波

本文导出了无外磁场电子注在等离子体约束下其上传播的空间电荷波波动方程，详细讨论了该条件下的波特性，并对等离子 频率降低因子进行了分析。研究了离子体填充状况空间电荷波性质影响甚大，选择等离子体填充因子对空间电荷波性质进行适当的控制。     

Excitation of microwave by an annular electron beam in a plasma-filled dielectric lined waveguide

An axial relativistic electron beam passing through a slow wave structure is unstable to an electromagnetic perturbation whose phase velocity equals the velocity of the beam. This phenomenon of Cherenkov emission is the basis of all traveling wave tubes. In this paper an excitation of Cherenkov radiation by a thin annular relativistic electron beam in a plasma-filled dielectric-lined waveguide is analysed by use of the self-consistent linear theory. The effect of the thin annular electron beam on the beam-wave interaction is completely described by a jump condition. The dispersion equation and the simultaneous condition of the beam-wave interaction are derived. Finally, the growth rate of the wave is obtained, and the effect of the background plasma density and the electron beam radius on the growth rate of the wave are presented.     

Cherenkov radiation with arbitrary azimuthal mode number excited in a plasma-filled slow-wave waveguide

On the basis of the reference [1], excitation of Cherenkov radiation with arbitrary azimuthal mode number by a thin annular relativistic electron beam in a plasma-filled dielectric-lined slow-wave waveguide is studied in this paper. A determinantal dispersion equation is obtained. This general dispersion equation is valid for arbitrary azimuthal mode number, and the growth rate of the wave is derived from it. Finally, the effects of the background plasma density on the dispersion relation, the background plasma density and the electron beam radius on the growth rate of the wave are presented. Formulas and results offerd in this paper are general, and are of particular value of reference to the beam-wave interaction in azimuthally unsymmetrical slow-wave waveguide.     

Mode analysis of an open-boundary cerenkov laser in the collective regime

The mode analysis of an open-boundary Cerenkov laser is developed in the collective regime. The Cerenkov laser under consideration consists of a relativistic slab electron beam and a dielectric-loaded conducting plane. The beam and the dielectric are assumed to be arbitrary in thickness, with an arbitrary gap allowed between them. For the Cerenkov laser specified above, the dependence of the growth rate upon the electron density of the beam, the beam-dielectric gap, the beam thickness, and the drift velocity of the beam is clarified. In particular, the following results deserve special attention. First, with other parameters kept invariant, the growth rate approaches a constant value for the beam thickness greater than the reactive skin depth of the beam. Second, the growth rate becomes maximum at the drift velocity of the beam characteristic of a particular electromagnetic wave mode with which the space charge wave interacts. As the mode number increases, the characteristic drift velocity shifts to higher values whereas the value of the maximum growth rate decreases.     

Mode analysis of a dielectric-loaded Raman-type free-electron laser

The Raman-type free-electron laser consists of a relativistic electron beam contained in a dielectric-induced parallel plate waveguide and an array of permanent magnets for the wiggler. Under the influence of the periodic magnetostatic field, the coupling between the scattered electromagnetic wave of the TE mode (positive-energy wave) and the electron plasma wave of the TM mode (negative-energy wave) is investigated in detail. The following results are obtained. First, when a dielectric sheet is loaded on the waveguide, the maximum growth rate and the oscillation frequency can be greater than those for the vacuum Raman-type free-electron laser. Second, by choosing proper values for the relative permittivity of the dielectric sheet and the ratio of the beam guide, the beam energy can be greatly lowered without degrading the oscillation characteristics. Third, the growth rate decays exponentially with the oscillation frequency kept almost constant as the beam-dielectric gap increases     

Linear Theory of Plasma-Filled Coaxial Cylindrical Cherenkov Maser

Injection of background plasma into the beam-wave interaction region can greatly enhance the beam-wave interaction efficiency and the microwave output power of the device. In this paper, a new type of plasma-filled slow-wave structure, i.e., plasma-filled, dielectric-loaded coaxial cylindrical waveguide with a dielectric ring enclosing tightly the inner conductor, is developed. The Cherenkov radiation excited by the beam-wave interaction in the slow-wave structure is examined by use of the self-consistent linear field theory. The dispersion equation and the synchronized condition of the beam-wave interaction are derived. It's clearly shown that the Cherenkov radiation excited by the beam-wave interaction results from the coupling between the slow electromagnetic wave, TM-modes, propagated along the slow-wave structure and the negative-energy space-charge wave propagated along the relativistic electron beam. And the wave growth rate is solved, and the beam-wave energy exchange in the presence of the background plasma is discussed. Finally, the effects of the background plasma density on the dispersion characteristics, the distribution of the longitudinal fluctuating electric field, the wave growth rate and the beam-wave energy exchange are calculated and discussed.     

Cherenkov radiation in a plasma-filled coaxial cylindrical dielectric slow-wave structure

In this paper, a new type of plasma-filled coaxial cylindrical dielectric slow-wave structure that is very beneficial to the beam-wave interaction of the high-power microwave source is developed. The Cherenkov radiation in the plasma-filled coaxial cylindrical dielectric slow-wave structure is examined by use of the self-consistent linear field theory. The dispersion equation and the synchronized condition as well as the wave growth rate of the beam-wave interaction are derived. The dispersion equation clearly shows that the Cherenkov radiation excited in the plasma-filled coaxial cylindrical dielectric slow-wave structure results from the coupling between the slow electromagnetic wave, TM-modes, propagated along the slow-wave structure and the negative-energy space-charge wave propagated along the relativistic electron beam. The numerical results indicate that the dispersion curves are divided into two branches due to the presence of the background plasma in the coaxial cylindrical dielectric slow-wave structure for the identical electromagnetic wave mode, and the radial distributions of the longitudinal fluctuating electric field corresponding to the two dispersion curve branches are completely different. Injection of the background plasma into the slow-wave structure can enhance the output frequency and the wave growth rate of the beam-wave interaction and enables the high-power microwave source that utilizes this kind of slow-wave structure to gain more output power of the microwave with higher output frequency.