Weizmann Institute of Science, Physics, Rehovot, Israel
FRIB, East Lansing, Michigan, USA
A bunch of ions injected into an accelerator, storage ring or ion beam trap will disperse over time. The electrostatic ion beam trap (EIBT), is a unique device where ions are stored between two electrostatic mirrors as a beam. Depending on the voltage configuration of the trap and the ion density, it can be operated in a diffusive mode or synchronization mode. The ion-ion interaction plays a role in either enhancing the diffusion process or establishing self-bunching among the ions. Using an external force perturbation like RF or chirp pulses, the phase space distribution can be significantly affected. For the case of RF bunching, we show that the nonlinear coupling between ions, which is the repulsive Coulomb interaction between them, restricts the growth of emittance within the RF bucket and keeps the bunch localized. Moreover using chirp pulses the accelerated bunches show evaporative cooling-like dynamics enhanced via ion-ion interaction for thermalization. A simulation technique bases on the particle is cell (PIC) has been developed to study the space charge effect on beam dynamics in the trap. The numerical results show a good agreement with the experimental observations.
