自由电子激光放大器的理论分析

本文从单粒子模型出发,对自由电子激光放大器在小信号情形下的工作机理与参量特性进行了比较详细的分析与讨论,结果表明自由电子激光放大器实质上是电子束与快迴旋波的相互作用,而电子在轴向均匀静磁场及横向周期静磁场中运动的迴旋谐振条件对这种相互作用有重大的影响,本文对放大器的参量(如电子束的电压和电流密度、轴向及横向静磁场强度、横向静磁场波长等)与放大器的中心工作频率、放大带宽、小信号增益和放大电磁波的波数的关系进行了数值计算,并指出了最佳设计的途径,经过适当设计,自由电子激光放大器的小信号增益达到10^-2厘米^-1或1米的e倍距离并有足够的带宽是不难的。 关键词：

THEORETICAL ANALYSIS OF FREE ELECTRON LASER AMPLIFIER

In this paper, a detailed analysis on the operating mechanism and parameter properties of free electron laser amplifier (FELA) in the case of small signal is presented. The results show that FELA is in essence the interaction between the electron beam and the fast cyclotron wave. The cyclotron resonance condition of electron motion in the uniform axial and periodic transverse static magnetic fields significantly influences the interaction process. We have calculated numerically the central operating frequency, band width, small signal gain and wave number of the amplified electromagnetic wave as functions of the parameters of the amplifier (such as the voltage and current density of the electron beam, the intensities of axial and transverse static magnetic field). The way to optimize the design of FELA is also suggested. It is possible to obtain a small signal gain of 10^-2 cm^-1 with enough band width in the millimeter and submillimeter range of weve length following a proper design.