PFC / JA - 89 - 48 A Planar Electromagnet Microwiggler for Free Electron Lasers

We have designed and tested an electromagnet planar microwiggler for use in free-electron lasers (FELs), constructed of current conductors wound on ferromagnetic cores. A prototype with a period of 1 cm and gap of 0.5 cm produced a peak field on axis in excess of 4.6 kG, with a linear B/H characteristic to about 3.2 kG. The field of each half-period of the wiggler is independently tuneable by adjusting the current delivered to each, thus allowing for precision tuning and/or wiggler tapering. We employ general scaling laws to predict performance of a geometrically similar design with a period of 5 mm. *This work was supported by the Office of Naval Research.