The Sagdeev pseudopotential method is used to investigate the occurrence and the dynamics of fully nonlinear electrostatic solitary structures in a plasma containing suprathermal hot electrons, in the presence of massive charged dust particles in the
background. The soliton existence domain is delineated, and its parametric dependence on different physical parameters is clarified.
The nonlinear propagation of electron-acoustic solitary structures is investigated in a plasma containing kappa-distributed (superthermal) electrons. Different types of localized structures are shown to exist. The occurrence of modulational instability is investigated.
