The Crystalline State of Ions
John Schiffer, ANL/PHY
Charged particles under external confinement will form an
ordered state if the kinetic energy in their relative motion
is small compared to the Coulomb repulsion between them.
Such a state has been observed in ion traps and may perhaps be
achieved in beams in storage rings. The nature of the ordering
is very much influenced by the finiteness of the systems and
the boundary conditions. The results of simulations will be
discussed in the context of experimental results. Phenomena
such as the quasi-crystalline ordering, dimensional phase
transitions and normal modes will be discussed, as well as the
problems associated with storage rings. Recent work on the
role of an effective 'temperature' in a dynamically confined
rf-quadrupole ion trap will be shown and results on the
coupling between periodic motion and random temperature.