Effects of misaligned electron beam on inverse free electron laser acceleration

In this paper, we discuss the effects of misaligned electron beam on an inverse free electron laser with both an electromagnetic wave wiggler and magnetostatic wiggler acceleration scheme. It is shown analytically that electromagnetic wiggler IFEL energy gain distance is substantially smaller when compared to the standard IFEL i.e. with a magnetostatic wiggler. The analysis further explains a better tolerance of the electromagnetic wiggler IFEL with respect to the misaligned electron beam in comparison to a magnetostatic wiggler IFEL scheme.