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The nonlinear fields in insertion devices can have a significant impact on the beam dynamics in storage rings. Various tools have been developed which allow the dynamical effects of a wiggler to be predicted, based on a detailed model of the magnetic field. The wigglers in the KEK-ATF have recently been commissioned, and provide an opportunity for benchmarking some of the analysis tools. We report on initial studies of the nonlinear effects of the KEK-ATF wigglers, based on studies of the change in betatron tunes with change in orbit through the wigglers, and compare the results with the predictions based on detailed field models.

Orbit Response Matrix (ORM) analysis is a technique used to diagnose and correct optics errors in storage rings. We report the results obtained from the use of ORM analysis at the KEK-ATF to reduce the equilibrium vertical emittance. Measurements of the vertical beam size using a laser wire indicate that the vertical emittance was successfully reduced from 12 pm to around 6 pm (at a bunch charge of 7e9 particles) using ORM analysis.

LOCO is a computer code for analysis of the linear optics in a storage ring based on the closed orbit response to steering magnets. The analysis provides information on focusing errors, BPM gain and rotation errors, and local coupling. Here, we discuss the details of the LOCO implementation at the KEK-ATF Damping Ring, and report the initial results. Some of the information obtained, for example on the BPM gain and coupling errors, has not previously been determined. We discuss the possibility of using the data provided by the LOCO analysis to reduce the vertical emittance of the ATF beam.