Experiments on transverse bunch compression on the Princeton Paul Trap Simulator experiment

The Paul trap simulator experiment is a compact laboratory Paul trap that simulates a long, thin charged- particle bunch coasting through a kilometers-long magnetic alternating-gradient (AG) transport system by putting the physicist in the beam´s frame-of-reference. The transverse dynamics of particles in both systems are described by the same sets of equations, including all nonlinear space- charge effects. The time-dependent quadrupolar electric fields created by the confinement electrodes of a linear Paul trap correspond to the axially-dependent magnetic fields applied in the AG system. Results are presented from experiments in which the lattice period is changed over the course of the experiment to transversely compress a beam with an initial depressed-tune of 0.9. Instantaneous and smooth changes are considered. Emphasis is placed on determining the conditions that minimize the emittance growth and the number of halo particles produced after the beam compression. Envelope equation solutions agree well with the experimental data.