High-current ion induction linac for heavy ion fusion : 2d3v numerical simulation

摘要

The 2d3v particle-in-cell simulations of the transport and acceleration of a high-current tubular ion beam through six magnetoinsulated accelerating gaps are presented. The ion beam is neutralized by an accompanying electron beam. The accelerating electric fields in the first, third, and fifth cusps are chosen so that electron beam kinetic energy is slightly higher than the potential barrier of the accelerating field in each cusp. The second, fourth, and sixth cusps are used for injection of additional high current electron beams. The accelerating fields in the second, fourth, and sixth cusps are zero. The simulations involve solving a complete set of Maxwell’s equations with charge-conserving schemes for calculating the current density on a mesh, and relativistic motion equations for charged particles. It is shown, that at chosen acceleration rates the quality of ion distribution function on the accelerator exit is not worsened drastically in comparison with the transportation mode. It is shown, that the optimized in space and time injection of additional high current electron beams in cusps results in increase of accelerated ion beam monochromaticity and to reduction it divergency on an accelerator exit.