Resonant excitation of betatron oscillations

Resonant excitation of betatron oscillations is a proposed mechanism for creating large amplitude, sinusoidal electron oscillations by overlaying a standard magnetic undulator and the radial electric fields of an ion channel to effectively create a very high strength undulator. By satisfying a resonance condition between the undulator and betatron periods, large transverse wiggling amplitudes are possible at short periods of oscillation. This skirts the existing limitations of magnetic undulators whose effective strength is constrained by the limits on high peak field values in a short (∼cm) period. Additionally, such motion can be achieved with on axis beam injection and greater operational amplitude and polarization tunability than offered in other incarnations of the plasma wiggler. This technique provides a path to applications that demand high K, tunable, bright x-ray or gamma ray radiation such as high flux polarized positron production and a practical realization of the ion channel laser.