Accession Number : ADA502659


Title :   Wall-Plug Efficiencies of High-Power Free Electron Lasers Employing Energy Recovery Linacs


Descriptive Note : Interim rept. Apr 2008-Apr 2009


Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC BEAM PHYSICS BRANCH


Personal Author(s) : Sprangle, Phillip ; Penano, Joseph ; Hafizi, Bahman ; Ben-Zvi, Ilan


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA502659


Report Date : 23 APR 2009


Pagination or Media Count : 28


Abstract : In a high average power free electron laser (FEL) the wall-plug efficiency is of critical importance in determining the size, complexity and cost of the overall system. The wall-plug efficiency for the FEL oscillator and amplifier (uniform and tapered wiggler) are strongly dependent on the energy recovery process. A theoretical model for electron beam dynamics in the energy recovery linac is derived and applied to the acceleration and de-acceleration of nano-Coulomb electron bunches for a tapered FEL amplifier. For the tapered amplifier, the spent electron beam exiting the wiggler consists of trapped and untrapped electrons. De-accelerating these two populations using different phases of the radio-frequency wave in the recovery process enhances wall-plug efficiency. For the parameters considered here, the wall-plug efficiency for the tapered amplifier can be -40% using this method.


Descriptors :   *FREE ELECTRON LASERS , OSCILLATORS , ELECTRONS , ELECTRON BEAMS , LINEAR ACCELERATORS , RADIOFREQUENCY , AMPLIFIERS , ELECTRODYNAMICS , HIGH POWER


Subject Categories : LASERS AND MASERS


Distribution Statement : APPROVED FOR PUBLIC RELEASE