The phonon wake behind a charge moving relative to a two-dimensional plasma crystal

In a recent experiment a wake was created in a two-dimensional lattice of c harged dust grains by a charge moving parallel to the lattice plane. Multip le "Mach cones" were observed in the wake. This paper describes a linear th eory of the phonon wake caused by a charge moving relative to a crystalline lattice. The theory predicts multiple structures in the wake that are qual itatively similar to those observed in the experiments. These structures ar e caused by constructive interference of compressional phonons excited by t he moving charge, combined with the strongly dispersive nature of these pho nons. (C) 2000 American Institute of Physics. [S1070-664X(00)04810-2].