Tunable microwiggler free electron laser experiment

Summary form only given. Computational and experimental studies of a tunable-amplitude microwiggler structure with a period of 1 cm which has produced on-axis fields exceeding 4.6 kG were performed. An order of magnitude reduction in random field errors, to 0.4% RMS, produced by amplitude tuning was demonstrated as compared to the untuned field profile. High-precision adiabatic up-taper field profiles were also obtained. Experimental saturation studies of the microwiggler were compared to computational models, linear B/H operation to 3.2 kG was observed. Preliminary experimental results demonstrating tunable transverse-plane focusing fields were obtained. An FEL experiment driven by a 450-kV Marx accelerator and a SLAC-style Pierce thermionic gun was proposed