On the Generation and Focusing of Intense Ion Beams for Pellet Fusion

The current limits of magnetic focusing systems are examined and approximate formulas for long solenoids and periodic channels with short lenses (solenoids and quadrupole doublets) are derived. The characteristics and limitations of conventional sources, pulsed ion diodes, and collective-field accelerators for the generation of intense, energetic ion beams are compared. Use of a collective-ion accelerator with debuncher is suggested as injector into an induction accelerator.