Besides the theoretical analysis , we also numerically studied the relation between the beam irregularity and b integral for a special four - pass amplifying system . based on these calculations , a " red line " has been set up for the safety of the system . in addition , the variation of beam irregularity with the size of filter ' s hole has been studied 在理论分析的基础上,我们用数值模拟的方法研究了一个具体的四程放大系统中光束非均匀性和b积分的关系,以此确定出了系统运行的“红线” (安四川大之户下员d匕论文全运行警戒线) ;同时探讨了滤波小孔尺寸与光束质量的关系。