Study of Lump Soliton Structures in Pair-Ion Plasmas

A theoretical investigation is carried out to study the lump soliton structures in hydrodynamical collisionless pair-ion plasmas, where electrons are modelled by Maxwell/Boltzmann distribution. A nonlinear Kadomstev-Petviashvili (KP) equation, which governs the evolution of lump solitary structures, has been derived using the reductive perturbation method. The lump soliton solutions of the KP equation representing nonlinear propagation characteristics are obtained using the Hirota bilinear approach. Combined effects of the different plasma parameters, viz. ion ratio, temperature ratio of positive ions to electrons and temperature ratio of negative ions to electrons, have been studied in detail, on the propagation properties of lump solitary structures. Both compressive and rarefactive lump solitons are observed in the present study. The findings of this study may be useful to understand the formation of nonlinear coherent structures in astrophysical environments as well as in laboratory experiments.