Emittance growth of ion beams with space charge

Abstract

Abstract Space charge induced emittance growth limits acceleration, transport and focusing in a vacuum, of heavy ion beams to be used for inertial confinement fusion. The mechanisms through which space charge can cause emittance growth are discussed as collective instabilities that render a phase space distribution unstable because of either a non-monotonic distribution function, anisotropy between different degrees of freedom or resonant coupling with the periodic focusing. Conclusions based on analytical calculations are compared with the results from a computer simulation with the particle-in-cell code SCOP2. In the final focusing in vacuum, collective effects are negligible. There remains, however, a relatively small single particle effect in the form of an aberration by the nonlinear space charge force.