Propagation of intense ion beams in straight and tapered z‐discharge plasma channels

A preformed z‐discharge plasma channel can be used to transport focused ion beams appropriate for a pellet fusion device. During transport, the beam can be compressed axially by time‐of‐fight bunching when appropriate ion accelerating voltage waveforms are employed. Single‐particle orbits in such channels are expressible in terms of simple harmonic functions for small ion injection angles. In this work, orbit analysis is used to investigate how nonuniformities or tapering of the channel and electric fields present in the channel affect radial beam confinement and power multiplication by bunching.