Speaker
Description
Longitudinal beam control using RF bunchers is widely employed in accelerators. However, the nonlinear RF fields in bunchers distort the longitudinal phase-space distribution, can lead to emittance growth. In this presentation, we report a self-linearization phenomenon observed for a 125 mA, 5 MeV deuteron beam in the Linear IFMIF Prototype Accelerator (LIPAc). In this mechanism, distortions induced by the nonlinear RF fields are partially compensated by longitudinal space-charge forces, leading to a reduction of the longitudinal rms emittance. TraceWin simulations are supported by analytical expressions describing the evolution of the phase-space distortion and the longitudinal space-charge-force distribution. Good agreement is obtained between the analytical model and the simulation results. These findings demonstrate that space-charge effects, generally regarded as detrimental to beam quality, can under certain conditions contribute to beam emittance reduction. The conditions under which this self-linearization mechanism arises, as well as its potential applications to phase-space control and beam-halo prediction in high-intensity accelerators, will also be discussed.