Study of the free electron maser

The basic idea that propagation of an electron beam through a rippled satic magnetic field could produce microwave radiation is due to Motz (1). Theoretical as well as experimental studies (2–4) have shown the practical possibilities of producing radiation in the infrared region using the electron beam of a LINAC with energies in the 20 to 50 Mev range. This device is now called a free electron laser and the production of radiation is interpreted as a single particle phenomena, the induced Compton scattering. However this interpretation has been criticized by Berstein and Hirshfield (5) because a standard plasma physics stability analysis of the beam/magnetic field interaction yields also to a coherent interpretation of the Standford experiment.