New coupling of dust-lattice modes with an external magnetic field

Dust-lattice modes (DLMs) are studied in a one-dimensional string of magnetized particles in a plasma crystal, associated with the particle-wake interaction and an allowable three-dimensional motion for each dust particle, in the longitudinal and transverse (vertical and horizontal) directions. The longitudinal and transverse (including vertical and horizontal types) modes for paramagnetized dust grains, due to the magnetic field direction, are coupled. For different directions of the magnetic field, dispersion relation gives three coupled modes. A novel type of oscillatory mode is found. The coupling can drive an instability and a damping of the modes, close to the point where their branches intersect. In addition to the wave amplitudes, we analyzed the change in the wave polarization for different magnetic fields (strength and direction) and for different wavenumbers.