Abstract: Coulomb interactions limit the brightness of charged particle beams. Controlling the effects of nonlinear beam expansion (space charge) and disordered inter-particle scattering is of critical importance for applications ranging from ultrafast electron diffraction to injectors for particle accelerators. In this talk I will show that ultra-cold ion bunches extracted from laser-cooled atoms can be used to observe the effects of Coulomb interactions with unprecedented detail. Arbitrarily shaped bunches are created to reverse the space-charge problem, and excitation of the cold atoms to Rydberg states prior to ionisation reduces the disorder-induced heating effect. I will present our experimental results that demonstrate improved beam brightness and models and simulations of the effects.