Transverse decoherence with space charge

After a transverse offset the amplitude of beam centroid oscillations decays due to the spread of individual particle frequencies. Decoherence of low intensity coasting beams can be described as the pulse response. However in heavy ion and proton beams, like in SIS100 synchrotron of the FAIR project, transverse space charge strongly modify this process. We present a model that explains the first stage of decoherence process in high intensity bunched beams. It uses the modified beam transfer function with space charge and image charges to calculate the pulse response. The model agrees with particle tracking simulations and measurements at the SIS18 synchrotron at GSI Darmstadt. The applicability region of the model was obtained.