Numerical study of free-electron lasers with reversed guide field

摘要

Abstract: al studies of the high efficiency results recently reported by Conde and Bekefi for a reversed field FEL are presented. These studies indicate that the predicted saturated power is rather sensitive to the detailed model used of the space-charge forces. The reported results for Group I FEL operation can be reproduced by increasing the emittance by 45% compared with the reversed field case. In this regime particle loss, rather than trapping, is the saturation mechanism. The Group II results are not consistent with the single-frequency model. A two-frequency model has been developed to study the influence of competition between the modes of the upper and lower FEL intersections. Initial results from this model indicates that the low power in the Group II experiment is not a consequence of mode competition.!5