Simulation of hollow beams with cancellation of steady state non-linear space-charge

This paper describes a technique for making multi-particle computer simulations of coherent instability consistent with conventional bunched-beam longitudinal instability theory. The argument behind the technique exposes an oversight of instability theory: the response of the phase-space distribution to the non-linear steady state wakefields is neglected. As an example, the technique is applied to a beam with the steady-state space-charge fields artificially canceled. The computer simulations presented are seen to agree with mode-coupling theory. Beam and machine parameters are taken from the proposed TRIUMF-KAON Accumulator, which is a high current proton storage ring