Equilibrium states of confined ions in two dimensions

Ions that are trapped in two dimensions and are subject to a harmonic confining potential have widely varying stationary states that exhibit various asymptotic forms and bifurcations. We present a ‘birds-eye’ view of these structures for N = 2 to 5 ions, and the full range of anisotropy. These results may be interrogated in detail using the software provided here. Energy variations at bifurcation points and limits are also identified; for N = 5 these include blue-sky (or saddle-node) bifurcations. A limited attempt is also made to explore such features for a larger system of ions, i.e. N = 10.