Periodic Magnets for Free Electron Lasers

Periodic magnets for free electron lasers may have either circular or linear field polarization, but in either case there is still little experience in the design, construction and operation of such special magnetic structures. Elias and Madey(1) have discussed the design and testing of the Stanford FEL magnet, and a number of other groups are now designing magnets for the new FEL projects. There is also experience at some laboratories in the operation of the same type of magnet for undulators, and this topic has generated much of the design work on periodic magnets(2–6).