Recent advances in the physics of collective excitations in the Paul trap simulator experiment

The Paul trap simulator experiment (PTSX) is a compact laboratory linear Paul trap that simulates the transverse dynamics of a long charged-particle bunch propagating through a magnetic alternating-gradient (AG) transport system. The transverse dynamics of particles in the AG system in the beamʹs frame-of-reference and those of particles in PTSX are described by the same sets of equations, including all nonlinear space–charge effects. Initial experimental results are presented in which the collective transverse symmetric mode ( m = 0 ) and quadrupole mode ( m = 2 ) have been observed in pure-barium-ion plasmas in PTSX, with a depressed-tune ν / ν 0 ∼ 0.9 , with the intent of identifying collective modes whose signature will serve as a robust diagnostic for key properties of the beam, such as line density and transverse emittance. The results of particle-in-cell simulations performed with the WARP code are compared to the experimental data.