Simulations of the TJNAF 10 kW free electron laser

The TJNAF Free Electron Laser (FEL) will be upgraded to operate at 10 kW average power in the near future. Multimode simulations are used to analyze the operation describing the evolution of short optical pulses in the far infrared wavelength regime. In an FEL that recirculates the electron beam, performance can depend on the electron beam distribution exiting the undulator. The effects of varying the undulator field strength and Rayleigh length of the resonator are explored, as well as the possibility of using an optical klystron. The simulations indicate that the FEL output power can reach the design goal of 10 kW.