Phase Shifts during Interaction between Two Solitons in Two-Dimensional Dusty Plasma

The dust acoustic solitary waves propagating in two different directions in two-dimensional dusty plasma are investigated. In order to study the soliton interactions in multi-dimensional systems, we extend the reductive perturbation method and obtain two Kortewe-de Vries equations for nonlinear waves in both the ξ and 77 directions, respectively. The phase shifts after collision of two solitons with arbitrary angle are given. Finally, the solution of na up to O（ε^4） order is obtained.