Abstract
The propagation of dust ion acoustic waves (DIAWs) in a collisionless, unmagnetized inhomogeneous dusty plasma containing warm positive ions, warm negative dust grains, and isothermal electrons is theoretically studied. The reductive perturbation method is employed to reduce the basic set of fluid equations to the variable coefficients Korteweg-de Varies (KdV) equation. It is found that both compressive and rarefactive solitons can propagate in the system. Below (above) certain value of positive ions density the system supports rarefactive (compressive) solitons. The dependence of solitons amplitude and width on the system parameters is investigated. It is noticed that the profile of the solitons are strongly affected by phase velocity and the density of dust grains as well as the dust grain charge number.