Self-consistent “start-to-end” simulation for free electron laser

“Start-to-end” simulation is widely used in the design and optimization of free electron laser (FEL) projects and it also plays an important role in the investigations of FEL physics. In this paper, a self-consistent “start-to-end” simulation approach is presented, in which all macroparticles are directly tracked from the photocathode to the undulator exit. The simulation principle is illustrated with the well benchmarked codes ASTRA, ELEGANT and GENESIS1.3. A numerical example about the low-charge operation mode of self amplified spontaneous emission (SASE) FEL is given and discussed. It shows that except for some slight differences, the results in the frame of the proposed approach agree well with that in the conventional one.