Eccentricity of the electron beam in a gyrotron cavity

Dependence of the coupling of the electron beam and RF field in a gyrotron cavity on eccentricity of the electron beam is studied.     

Development of a fast risetime pulsed relativistic electron beam generator for the excitation of shorter wavelength lasers

We have developed a compact and simple high current relativistic electron beam (REB) generator for the excitation of lasers in the shorter wavelength region. This REB generator mainly consists of a Tesla transformer-type high-voltage generator, N₂ gas insulated Blumlein-type pulse-forming line and cold-cathode electron gun to generate 800 keV, 12 kA pulsed electron beams with 6 ns current duration and approximately 4 ns current risetime. The design and operational characteristics along with discussions of the excitation capabilities of the gas laser media are presented in this paper.     

Interaction of a relativistic electron beam with a spiral waveguide

The nonlinear period in the interaction of a relativistic electron beam (REB) with an electromagnetic wave in a spiral waveguide at the stage of saturation is investigated for a Cherenkov interaction mechanism. On the basis of the kinetic equation and laws of energy and momentum conservation, analytical relations are obtained, allowing the efficiency of excitation and amplification of the electromagnetic wave to be studied using REB in a retarding structure. The results of the analysis are in good agreement with the data of actual and numerical experiments.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 31–36, May, 1988.It remains to thank É. A. Perel'shtein, Yu. I. Aleksakhin, and their colleagues for discussion of the results.     

回旋电子束横纵速度比测试技术

摘要:通过对回旋电子束形成的电位和电场分布,推导出电子束横纵速度比测量的计算式.提出将电子束作传输线内导体等效,采用陶瓷电容分压器来测量速度比的方法.介绍了该测量装置的设计和加工工艺,及陶瓷电容分压器的标定方法和结果分析,并介绍了初步的原理性实验结果.该测试方法装置简单,测试电子束横纵速度比时不会破坏电子束的特性,能够...     

Experimental studies of gyrotron electron beam systems

In order to provide electron beams of powerful gyrotrons, magnetron-injection guns operating in the regime of the temperature limited current are used. The electron beam quality and gyrotron performances are defined both by the cathode emission processes and the processes occurring in the electron beam during its formation and transportation. The results of measurements of the energy spectrum and velocity spread of the gyrotron electron beam in different regimes are given. Experimental data on the parameter of efficient emission inhomogeneity for different regimes are presented, as well as the dependencies of electron beam parameters on efficient inhomogeneity of the cathode     

回旋电子束横纵速度比测试技术

通过对回旋电子束形成的电位和电场分布,推导出电子束横纵速度比测量的计算式。提出将电子束作传输线内导体等效,采用陶瓷电容分压器来测量速度比的方法。介绍了该测量装置的设计和加工工艺,及陶瓷电容分压器的标定方法和结果分析,并介绍了初步的原理性实验结果。该测试方法装置简单,测试电子束横纵速度比时不会破坏电子束的特性,能够做到在回旋管运行时在线测量,实时监测电子束质量。     

激光驱动强流电子束产生和控制

在惯性约束聚变（ICF）电子束快点火物理方案中,需要超强拍瓦激光脉冲驱动MeV能量的强流电子束,并沉积数十kJ能量到压缩氘氚芯区。强流电子束的束流品质是影响点火成功的关键因素之一,为深入了解强流电子束产生物理过程,研制成了三维高性能、适应上万CPU核规模的并行粒子模拟程序,并开展了大规模数值模拟研究,探索了强流电子束的产生机制和输运规律。回顾了近几年来快点火研究团队围绕强流电子束产生和控制开展的研究,介绍了导致束流品质差的两大物理原因：预等离子体效应和束流不稳定性磁场的随机散射。针对这两个物理原因,提出了四种提高强流电子束品质的方法：（1）双层金锥靶减弱预等离子体的负面效应;（2）输运丝产生环向磁场准直强流电子束;（3）外加磁场导引强流电子束提高耦合效率;（4）抑制束流不稳定性以降低随机磁场对电子束流的散射。     

激光驱动强流电子束产生和控制

在惯性约束聚变(ICF)电子束快点火物理方案中,需要超强拍瓦激光脉冲驱动MeV能量的强流电子束,并沉积数十kJ能量到压缩氘氚芯区。强流电子束的束流品质是影响点火成功的关键因素之一,为深入了解强流电子束产生物理过程,研制成了三维高性能、适应上万CPU核规模的并行粒子模拟程序,并开展了大规模数值模拟研究,探索了强流电子束的产生机制和输运规律。回顾了近几年来快点火研究团队围绕强流电子束产生和控制开展的研究,介绍了导致束流品质差的两大物理原因:预等离子体效应和束流不稳定性磁场的随机散射。针对这两个物理原因,提出了四种提高强流电子束品质的方法:(1)双层金锥靶减弱预等离子体的负面效应;(2)输运丝产生环向磁场准直强流电子束;(3)外加磁场导引强流电子束提高耦合效率;(4)抑制束流不稳定性以降低随机磁场对电子束流的散射。     

Space charge effects in a gyrotron employing a solid electron beam

The influence of space charge forces on the performance of a single cacity gyrotron oscillator which uses a solid electron beam was investigated. It was found that space charge effects cause a large efficiency degradation as the beam current is increased, if the other experimental parameters are unchanged. A small increase in the magnetic field, however, can restore the efficiency to higher values.This research was supported by the U.S. Office of Naval Research.     

大回旋cusp电子注数值模拟

新一代宽带、高增益、大功率回旋行波管需要新型的电子注,而大回旋cusp电子注为其实现提供了可能。对大回旋cusp电子注进行系统理论分析,建立了大回旋cusp电子注的物理模型,在理论分析基础上进行了大量数值计算和模拟优化,并对大回旋cusp电子枪设计中的影响因素进行探讨。设计出一支低速度零散、高速度比、低纹波,适用于高次谐波的高功率(54 kV, 2.7 A)cusp电子枪。     

大回旋cusp电子注数值模拟

 新一代宽带、高增益、大功率回旋行波管需要新型的电子注,而大回旋cusp电子注为其实现提供了可能。对大回旋cusp电子注进行系统理论分析,建立了大回旋cusp电子注的物理模型,在理论分析基础上进行了大量数值计算和模拟优化,并对大回旋cusp电子枪设计中的影响因素进行探讨。设计出一支低速度零散、高速度比、低纹波,适用于高次谐波的高功率(54 kV, 2.7 A)cusp电子枪。     

The dissipative instability of a relativistic electron beam

The theory of the wall instabilities of surface waves excited by an electron beam is developed. Their classification, linear, quasilinear and nonlinear theory is given. It is shown that dissipative instabilities convert practically all the energy lost by the beam into the heating of the lossy walls confining the beam.     

Anomalous scattering of a relativistic electron beam in a beam created plasma

Measurements of the velocity angular distribution of a relativistic electron beam (0.8 MV, 6 kA, 150 ns) after propagation through hydrogen gas are presented. At a pressure of 25 Pa scattering of the beam electrons into a preferential angular interval is observed. At 190 Pa anomalously large scattering is observed, up to an angular width of 90°, during about 30 ns.     

Removal of nitrogen oxide in spatially isolated chamber by pulsed intense relativistic electron beam

Nitrogen oxide (NO/sub x/) in a chamber spatially isolated from beam source has been removed by a pulsed, intense, relativistic electron beam (PIREB). The chamber is filled up with dry-air-balanced NO/sub x/, and is irradiated by the PIREB (2 MeV, 2.2 kA, 85 ns) passing through 1.6-m-long atmosphere. The NO/sub x/ concentration decreases from 88 to 25 ppm by ten shots of PIREB.     

Developing a high-current relativistic millimeter-wave gyrotron

A relativistic gyrotron fed by a 500 keV, 2 kA helical electron flow in the TE and TM modes is simulated on the basis of a self-consistent system of time-dependent equations with a non-fixed field structure and using a three-dimensional version of the KARAT PIC code. The possibility of reaching an output power 200–250 MW at a wavelength of 10 mm is shown.     

Diocotron instability of the electron beam in the drift tube of a gyrotron

A cold fluid model is used to investigate instabilities associated with a velocity shear due to the self fields of a relativistic electron beam inside the beam tunnel of a gyrotron. General statements concerning the stability of an electron beam like the frequency and the growth rate are possible. The growth is expressed as a length that can be compared with the geometry in the gun-tube-resonator system.