Theoretical study of segmented undulator phase matching

Phase matching between different undulator segments is a key condition for high gain Free Electron Laser facilities to gain saturation laser output. This paper develops theoretical study on phase matching, provides the scheme to realize it and gives the parameters of terminations structure. According to the simulation result, ±100 degree phase adjustment range can be achieved when the pole height can be adjusted in the range of ±0.5 mm. (authors)