Dust acoustic soliton and shock structures with consequence of head-on collision in multi-component unmagnetized plasmas

An unmagnetized plasma system comprising Maxwellian electrons, nonthermal ions, and variable negative charged dust grains is considered to investigate the consequence of head-on collision (such as interaction processes, and phase shifts) and the formation of dust acoustic soliton as well as shock structures in the Halley’s Comet (HC), Interstellar Clouds (IC), Noctilucent Clouds (NC), and Saturn’s Spokes (SS) environments. The two-sided Korteweg de Vries Burger (KdVB) and Korteweg de Vries (KdV) equations and corresponding phase shifts are derived employing the extended Poincaré-Lighthill-Kuo (ePLK) reductive perturbation technique (ePLKRPT). The coefficient of nonlinearities vanishes in each environment at the critical value of the plasma parameters. Consequently, the nonlinearity-coupled modified KdVB (mKdVB) and modified KdV (mKdV) equations, and the associated phase shifts have been derived. The concerned parameters play a crucial role in forming soliton and shock structures, phase shifts, and the interaction process of solitons and shocks in each environment. The compressive hump-shaped structures for mKdV solitons, as well as only positive phase shifts, are produced due to the influences of concerned parameters in each environment. In the collision processes, both the KdV and mKdV dust acoustic solitons follow the principle of superposition, but the shocks do not follow the principle of superposition.