Research on the miniaturization of FEL

According to the analysis on output wavelength of FEL,this paper point out that a one of main research fields of miniaturization of FEL is micro-wiggler.Based on the study of present situation of the small-period wiggler.a new current wiggler is presented.The wiggler has a same function as a permanent-magnet wiggler,its period cab be also regulated automatically,Therefore,the current wiggler can be used widely.Finally,this paper point out the problems of further research.