Normal modes of 2D finite clusters in complex plasmas

Finite clusters with a small number of charged particles immersed in a complex-plasma environment have been investigated experimentally. Finite clusters in complex plasmas are shown to be a unique system for the excitation and observation of normal modes in bounded charged-particle systems. In systems of 3, 4, and 7 particles, normal-mode oscillations have been excited and from the frequencies of the different modes the key parameters, particle charge, and the screening strength have been derived. This method is proposed to be applied in future microgravity experiments.