Experiments on metastable states of three-dimensional trapped particle clusters

Small three-dimensional charged-dust clusters, so-called Yukawa balls, are analyzed with regard to their construction principle. For that purpose, in an experimental approach, different (metastable) configurations of clusters with fixed particle number (N<100) have been generated under identical plasma and trapping conditions. Metastable states are frequently observed. In combination with molecular dynamics simulations, it is shown that particle interaction with screening strongly affects the appearance probabilities of metastable configurations. Small clusters show different average density distributions with screened interaction compared to pure Coulomb, although having the same ground state configurations.