Formation of dust acoustic rarefactive solitary structures in a Cairns distributed electron–ion plasma

The Cairns-distributed electrons and positive ions in a plasma made up of a negative dust fluid are taken into account to examine the presence of arbitrary amplitude dust-acoustic solitons. It has previously been noted that nonthermal ions and thermal electrons generate both compressive and rarefactive solitons. In this paper, we noticed that nonthermal electrons together with nonthermal ions are responsible for producing the rarefactive solitons. It is found that the Sagdeev potential strongly depends on plasma parameters, such as nonthermal index α and Mach number, which, in turn, influence the Sagdeev potential and solitons significantly. We also found that the critical match number and height of soliton increase with the nonthermal parameter α. We further note that the Sagdeev potential as a function of potential φ becomes more negative and the amplitude of the soliton also enhances as the value of Mach number rises. It is concluded that the model presented here based on nonthermal ions and electrons in a negative dust fluid provides a worthy interpretation for electrostatic solitons observed in space plasmas.