Preparation of Mesoscopic Ion Crystals at SpecTrap

We have studied the formation process of mesoscopic Coulomb crystals in a Penning trap. The ion plasma (see picture) contains several thousand laser cooled Mg⁺ ions. The ions arrange into a multi-layer crystal because of their extremely small kinetic energy after cooling. In future, these Coulomb crystals will serve as a cold target for sympathetic cooling of highly charged ions.