Modeling of WLS field with piecewisely constant magnets

A WLS, or a wavelength shifter, is a superconducting wiggler which, installed as an insertion device (ID) in a storage ring, can provide short wavelength synchrotron light and will usually impose a strong effect upon the stored beam. We focus on: estimation of the biggest 1st and 3rd order terms with field integrals; linear effect modeling by parameter fitting. Most methods and ideas described, such as the “higher order edge effect”, apply in principle to other ID´s