Ions trapped in a harmonic potential of the form z^2 + alpha r^2.
The number of ions of equals 4, shown as pink spheres. To see other cases,
click on :
Two blue squares are placed at z = +-2 to show the z axis.
The crystal may be viewed from different angles using the mouse.
The buttons and the slider control the value of alpha (eg. alpha=1 => spherical potential well).