Charge gradient effects on modulated dust lattice wave packets in dusty plasma crystals

Nonlinear Dust lattice modes are studied in a hexagonal two-dimensional dusty plasma lattice, in presence of charge gradient of dust particles. In this lattice, such gradients affect nonlinear behavior of dust lattice waves. The amplitude modulation of off-plane transverse dust lattice wave packets is investigated considering the anisotropy of interactions, caused by the height-dependent charge variations. A nonlinear Schrodinger equation described time evolution of modulated off-plane transverse dust lattice wave packet. Calculations show that the charge gradient changes the stability condition of the solution of the nonlinear Schrodinger equation.