改型Wiggler自由电子激光谐波产生的非线性理论

Noulinear Theory of Harmonic Generation in an FEL with Modified Wiggler

建立了改型Ｗｉｇｇｌｅｒ自由电子激光的非线性理论。导出了自洽非线性方程组。用计算机模拟了在改型Ｗｉｇｇｌｅｒ磁场中，电子与光场互作用从线性调制到非线性饱和的演化过程，得到了电子的相空间群聚图、高次谐波的增益、抽取效率和电子束的分布函数。同时还研究了电子束的能散度对高次谐波的增益和效率的影响等。模拟结果证实，改型ｗｉｇｇｌｅｒ自由电子激光是实现短波长相干光辐射的重要途径之一。

This paper investigates the nonlinear theory of the modified wiggler FEL and presents a set ofnonlinear seif-consiment equations.The evolutional process of electrons interact with the optical field in amodified wiggler from linear modulation to nonlinear saturetion is simulated.and the benching plots of electronphase space,the gain of higher harmonics drawn efficieny and elctron distribution function are obtained.Theinfluence of electron energy spread on gain and efficiency of higher harmonics is also studied. Simulation resultsverify that a modified wiggler FEL is an important way to realize short wavelength coherent rediation.