Electrostatic solitary structures in a dusty plasma with dust of opposite polarity

A four-component dusty plasma consisting of electrons, ions, positively charged warm adiabatic dust, and negatively charged cold dust is considered. The basic features of the electrostatic solitary structures in such a four-component dusty plasma are investigated by the reductive perturbation method, which is valid for the small amplitude solitary waves, and by the pseudopotential approach which is valid for the arbitrary amplitude solitary waves. It is found that the presence of the positive dust component does not only significantly modify the basic properties of the solitary potential structures, but also causes the coexistence of the positive and negative solitary potential structures, which is an interesting feature shown in a dusty plasma with the dust of opposite polarity. The basic features and the underlying physics of the electrostatic solitary structures, which are relevant to cometary tails, upper mesosphere, Jupiter's magnetosphere, etc., are briefly discussed.