Space-Charge Experiments at the CERN Proton Synchrotron

Benchmarking of the simulation codes used for the design of the next generation of high beam power accelerators is of paramount importance due to the very demanding requirements on the level of beam losses. This is usually accomplished by comparing simulation results against available theories, and more importantly, against experimental observations. To this aim, a number of well‐defined test cases, obtained by accurate measurements made in existing machines, are of great interest. Such measurements have been made in the CERN Proton Synchrotron to probe three space‐charge effects: (i) transverse emittance blow‐up due to space‐charge induced crossing of the integer or half‐integer stop‐band, (ii) space‐charge and octupole driven resonance trapping, and (iii) intensity‐dependent emittance transfer between the two transverse planes. The last mechanism is discussed in detail in this paper and compared to simulation predictions.