Intermittent ion leakage from a Penning trap during potential barrier closure

Intermittent leakages of trapped ions from a Penning trap are clearly explained. Two mechanisms are revealed by considering both experimental and numerical results. The initial leakage is due to ions energized by the potential barrier that is just closing to form a positive potential well. The following leakage is induced by an axial average oscillation of the bulk of the trapped ions. Some individual bounce ions are pushed out of the potential barriers owing to the space potential of the bulk.