毫米波自由电子激光的空间电荷效应

本文编制了三维数值模拟程序,考虑了电子在摇摆器(Wiggler)内纵向速度β^z=υ^z/c<1的影响,考虑了电子在有质动力势阱中因"群聚"而引起的纵向空间电荷力的影响,考虑了电子束内静电波和激光场、Wiggler静磁波的三波相互作用对电子位相的影响等。对因"群聚"而引起的纵向电场满足的方程求出了近似的二维解析解,用4096个电子模拟求解了电子运动方程和光场方程。数值模拟的结果和Livermore实验室的实验结果进行了比较。结果表明,由于上述几项因素的考虑,我们的数值模拟结果和实验位基本一致,消除了文献1,2,3]中出现的失谐曲线(detuning curve)峰值磁场漂移300-500高斯的差距。

SPACE-CHARGE EFFECTS IN MICROWAVE FREE ELECTRONLASER

A 3-dimensional numerical simulation code for microwave FEL in which space-charge force have been in eluded approxi matelv is worked out. The code constitutes of the electrons' energies and pandermotive phases according to the averaged single-particle equations derived by KMR, and the fields according to the paraxial wave equation. The particle motion is fully three-dimensional. The field solver is accurately three-dimensional for microwave simulation. The simulated results show that longitudinal space-charge force reduce the gain and saturation power about 15%,and increase the synchrotron period of the electrons.