The NonLinear Theory of the Free Electron Laser

Abstract

The free electron laser (FEL) is a new radiation source characterized by frequency tunability, high power levels, high efficiencies and output wavelengths ranging from the millimeter to beyond the optical regime. The schematic of the FEL configuration consists of a stream of relativistic electrons propagating through a spatially periodic wiggler field as depicted in Fig. 1. Under appropriate conditions, an electromagnetic wave double doppler upshifted in frequency can be amplified.