Head-on collision of ion-acoustic waves in multi-component unmagnetized plasmas

Face-to-face collisional effects of ion acoustic waves (IAWs) in multi-component unmagnetized plasma containing pair-ions, nonthermal electrons and isothermal positrons are investigated theoretically. The nonlinear Korteweg-de Vries (KdV) equations are derived employing the extended Poincare-Lighthill-Kuo (ePLK) method to perceive the consequences of collisions of IAWs on amplitude, width and phase shift taking into account the concerned plasma parameters. This study reveals that the compressive (hump shape) and rarefactive (dip shape) solitons as well as the negative phase shifts are produced depending on plasma species densities, temperatures and collisions. The nonlinear coefficient of IAWs is increasing due to the changes in the mass ratio of positive to negative ions, density ratio of electron to positive ion and temperature ratio of electron to positron. The results of this study can be useful understanding in different regions of space (viz., upper region of Titan's atmosphere, cometary comae and Earth's ionosphere, etc.) and laboratory (viz., plasma processing reactor and neutral beam sources, etc.) plasmas.