Collective excitations of a spherically confined Yukawa plasma

Abstract

The results of a recent fluid theory for the multipole modes of a Yukawa plasma in a spherical confinement [H. K\"{a}hlert and M. Bonitz, Phys. Rev. E \textbf{82}, 036407 (2010)] are compared with molecular dynamics simulations and the exact $N$-particle eigenmodes in the crystalline phase. Simulations confirm the existence of high order modes found in cold fluid theory. We investigate the influence of screening, coupling and friction on the mode spectra in detail. Good agreement between theory and simulation is found for weak to moderate screening and low order modes. The relations between the breathing mode in the fluid theory, simulation and the crystal eigenmode are investigated in further detail.