Chaotic Particle Motion in Hadron Storage Rings Exhibiting Decreasing Betatron Amplitudes

In the regime of stabilized resonances chaotic motion is a precondition for particle loss in hadron storage rings. But chaoticity does not necessarily lead to loss on a limited time scale. A variety of phenomena can be observed, among them particles with decreasing betatron amplitudes. Chaotic proton motion, created by strong nonlinearities and tune modulation, was studied in an experiment at the CERN SPS. The particle motion was investigated over several minutes in the vicinity of an 8th order resonance. Element-by-element tracking and a theoretical analysis preceded and accompanied the experimental work.