The propagation of a nonlinear wave packet of dust lattice waves (DLW) in a two-dimensional hexagonal crystal is investigated. The dispersion relation and the group velocity for DLW are found for longitudinal m and transverse n propagation directions. The reductive perturbation method is used to derive a (2 + 1)-dimensional nonlinear Schrödinger equation (NLSE) that governs the weakly nonlinear propagation of the wave packet. This NLSE is used to investigate the modulational instability of the packet of DLW. It is found that the instability region is different for different propagation directions.
- dust lattice waves
- non-linear propagation