Space-charge wave propagation in inhomogeneous waveguides

Abstract

In this paper, an account is presented of an investigation into the propagation of large amplitude space-charge waves in an inhomogeneous waveguide. The study is motivated by the possibility of using these waves for the collective acceleration of ions. Measurements are reported that show an increase in the wave phase velocity as the guide diameter, and hence the effective plasma frequency is decreased. Results are also presented which show that the wave phase velocity is a function of its amplitude, and that large amplitude, nonlinear waves propagate more slowly than those described by linear theory. The results demonstrate that it is possible to control the wave propagation characteristics, and therefore indicate the electron-beam-supported slow space-charge waves provide a suitable medium for collective ion acceleration. Finally, a summary is given of possible advantages of an electron beam-wave accelerator over those using externally generated rf fields.