Extension of Busch's theorem to particle beams

Abstract

In 1926, H. Busch formulated a theorem for one single charged particle moving along a region with longitudinal magnetic field. The theorem relates particle angular momentum to the amount of field lines being enclosed by the particle cyclotron motion. It has been extended to accelerated particle beams. This contribution sketches the extension and applies the extended theorem to successfully performed emittance manipulations with electron and ion beams.