中文摘要：

讨论近年出现的分析自由电子激光系统饱和状态性质的一种统计物理方法.对于自由电子激光系统激光增益达到饱和时的主要物理参数所满足的方程作了推演,进而基于统计物理方法利用Lynden-Bell熵函数和Mathematica程序进行了相关的数值计算和分析.为了对这一方法作验证和对比,通过直接数值模拟的方法分析了暖电子束入射情形下系统光强、聚束因子和粒子相空间分布的性质以及它们之间的对应关系,比较显示数值模拟结果与统计物理方法的相应结果一致.

英文摘要：

A new approach employing statistical physics was discussed to predict the characteristics of the saturated state of a high-gain free-electron laser （FEL）. The equations of the physical parameters for free-electron lasers at saturation were deduced,and by Mathematica code relevant numerical simulations employing the Lynden-bell entropy were performed. Through direct numerical simulations of the dynamical equations using Mathematica,an analysis was conducted of the radiation intensity,bunching parameters and electron distributions in phase space at saturation of FEL to validate the feasibility of the proposed method. It is shown that the results by these numerical simulations are in good agreement with those by the proposed approach.