Research on Free Electron Lasers

The research includes the derivation of better high-efficiency equations for describing the FEL in the strongly saturated regime. The equations retain much of the simplicity of the old theory, but are accurate for high energy extraction. The dimensionless parameters of the equations are used to describe the LANL and LLNL FEL experiments. In a publication, the importance of the dimensionless current density j is emphasized for describing many diverse FEL physical effects. The effects of waveguides on the FEL radiation interaction are derived and presented in this report. The ELF FEL amplifier used a wave guide and is used as an example. It was found during the study that the gain spectrum of high-gain amplifiers like ELF can have sharp spikes. The spikes are not related to the use of a waveguide, but are an important result of this contract. A review paper invited by SPIE discusses some the techniques used to simulate FELs of many different kinds. Keywords: Mathematical equations; Free electron lasers. (kt)