Number 83 (Story #1), June 8, 1992 by Phillip F. Schewe and Ben Stein IONS IN STORAGE RINGS can form ordered structures such as linear, zig-zag, helical, or concentric-ring arrangements. Experimenters at the Max Planck Institute for Quantum Optics in Garching, Germany use a ring-shaped ion trap (11.5 cm diameter) to store laser-cooled magnesium ions. Drawing on the technology of previous (essentially one-dimensional) traps that confine a relatively small number of ions to a pointlike space (the center of the trap), the Garching scientists store thousands of ions in a (two-dimensional) space with a ring geometry. The advent of ordered structures in storage rings would help atomic physicists conducting high-precision spectroscopy and would benefit accelerator physicists by making possible beams with higher luminosity and smaller momentum spread. (Nature, 28 May 1992.)