Simulation of the debunching process and adiabatic r.f. capture of intense beams

The high intensity beam of an inertial confinement fusion storage ring will be affected by strong space charge fields. We have studied the emittance growth during debunching of an intense linac beam and adiabatic r.f. capture in the storage ring under the influence of the self-consistent space charge force. The particle motion is simulated with the particle-in-cell code SCOP-RZ neglecting particle collisions. The results show that rebunching can dramatically reduce the growth of the momentum spread during the debunching process. A funnelling injection scenario is proposed, which avoids the final emittance growth following the rebuncher. We estimated the total r.f. ramping time needed for adiabatic r.f. capture. This ramping time is short enough to prevent particle losses due to intrabeam charge exchange.