<title>Self-consistent analysis of wiggler imperfections in free-electron lasers</title>

Abstract

A self-consistent analysis of weight field errors in free-electron lasers is described using the 3D simulation code WIGGLIN. The 3D wiggler field model chosen is able to treat gradients in the wiggler amplitude since both the divergence of the field as well as the axial component of the curl vanish identically while the transverse components of the curl are small. Hence, the field model is well-suited to the treatment of small imperfections in the wiggler amplitude. In order to describe the wiggler imperfections, a random variation is chosen to determine the pole-to-pole variations in the wiggler amplitude and a continuous map is used between the pole faces. The specific parameters chosen for study correspond to the high-power 35-GHz free- electron laser experiment conducted at Lawrence Livermore National Laboratory; however, the fundamental physics issues are relevant to the entire range of free-electron laser experiments.