EM－FEL边带不稳定性的动力学理论

Kinetic Theory of EM-FEL Sideband Instability

本文从Ｖｌａｓｏｖ－Ｍａｘｗｅｌｌ方程出发，利用沿未扰轨道积分的方法，建立了无引导磁场电磁波泵自由电子激光（ＥＭ－ＦＥＬ）的动力学理论．首先讨论了在平衡状态下电子运动的特性，然后求出了普遍的色散方程．导出了平衡态分布函数分别为均匀分布、单能量分布和递减分布三种情况下的色散方程，求出了均匀分布情况下边带不稳定性最大线性增长率及相应的频率．对色散方程进行了数值计算．分析了ＥＭ－ＦＥＬ边带不稳定性的特点．

Kinetic theory of sideband instability for an electromagnetic pump free-electron laser (EM-FEL) without a guided magnetic field has been developed by applying Vlasov-Maxwell equations and integration along the unperturbed orbit.The properties of electron motions in the equilibrium distribution have been discussed and the general dispersion equation is derived. The maximum linear growth rates and the relavent frequencies of sideband for step distribution have been obtained. Numerical calculations for the dispersion equations are carried out.The properties of the EM-FEL sideband instability have been discussed in detail.