Paper  Title  Page 

MOP063  A Novel Modeling Approach for Electron Beams in SASE FELs  190 


We have recently shown that the WheelerFeynman analysis of the interaction of a moving charge with distant absorbers [*] provides a perfect match to the energy radiated by two coherently oscillating charged particles (a heretofore unsolved problem in classical electrodynamics) [**]. Here we explain the need to include the WheelerFeynman coherent radiation reaction force as an integral part of the solution of the boundary value problem of free electron lasers (FELs) that radiate into “free space”. We will also discuss how the advanced field of the absorber can interact with the radiating particles at the time of emission. Finally we will introduce and explore the possibility of improving the temporal coherence in the self amplified spontaneous emission (SASE) FELs as well as the possibility of optimizing the spectrum of the emitted coherent radiation by SASE FELs via altering the structure of their targets by including the WheelerFeynman coherent radiation reaction force in the analysis of FEL operations.
* Wheeler, J. A.; Feynman, R. P, Rev. Mod. Phys. 17, 157, 1945. ** P. Niknejadi et al. "Energy Conservation of Coherently Oscillating Charged Particles in Classical Electrodynamics" submitted. 
