Electrostatic solitary structures in a charge-varying pair-ion-dust plasma

Large-amplitude electrostatic solitary structures are investigated in an unmagnetized charge-varying pair-ion-dust plasma in which electrons and positrons have equal masses. Their spatial patterns are significantly modified by the presence of the positron component. In particular, it may be noted that an addition of a small concentration of positrons abruptly reduces the potential pulse amplitude as well as the net negative charge residing on the dust grain surface. Under certain conditions, the solitary wave suffers the well-known anomalous damping leading to the development of collisionless shock waves. This investigation may be taken as a prerequisite for the understanding of the electrostatic solitary waves that may occur in space dusty plasmas.