COHERENT RADIATION IN INSERTION DEVICES

We calculate the coherent radiation in an undulator/wiggler with a vacuum chamber of arbitrary cross section. The backward radiation is a coherent and it has wavelengths about twice the period of the undulator/wiggler. Mostly of coherent radiation is going with the wavelengths approximately the bunch length at small angles however. Classification 3: Linear Colliders, Lepton Accelerators and New Acceleration Techniques, T19. Work supported in part by NSF grant PHY-0202078, RFBR Grant 09-02-00638a