Head-on collisional effects of ion acoustic waves in pair-ion plasma: topological and non-topological solitons

Abstract

The phenomena concerning head-on collision between the two topological and non-topological solitons are investigated in unmagnetized and collisionless plasma system consisting of weakly relativistic cold positive ($H^{+}$, ${Xe}^{+}$ and $K^{+}$) and negative ($H^{-}$, ${SF}_{6}^{-}$, $O_{2}^{-}$ and $C_{7}F_{14}^{-}$) ion species with superthermal electrons. To do this, the two-sided Korteweg–de Vries (KdV) equations are derived using extended Poincaré–Lighthill–Kue method. The solutions of KdV equations are obtained by solitary ansatz technique. Productions as well as collisional effects of non-topological and topological solitons are investigated taking the experimentally obtained plasma parameters into accounts. The study reveals that the nonlinearity of non-topological solitons become more pronounced for $K^{+}-C_{7}F_{14}^{-}$ plasma as compared to the other ionic species plasmas. The masses and densities of negative ion species play a vital role on the potential profiles of topological solitons. A new type large amplitude wave is produced in the colliding region due to collision depending on plasma parameters.

Graphic abstract

Appendix A

The number density of Maxwellian electrons is [According as Ref. 74]

$$\begin{aligned} n_{e}=e^{-\frac{e{\Phi }}{\kappa _{B}T_{e}}}. \end{aligned}$$

(A1)

The normalized form of (A1) can be written as:

$$\begin{aligned}&\displaystyle n_{e}=e^{-\phi }\approx 1-\phi +\frac{1}{2}\phi ^{2}+\cdots . \nonumber \\&\displaystyle \hbox {That is}, \qquad n_{e}\approx 1+a\phi +b\phi ^{2}+\cdots . \end{aligned}$$

(A2)

$$\begin{aligned}&\displaystyle \hbox {Where} \,\, a=-1 \, \hbox { and } \, b=\frac{1}{2} \end{aligned}$$

(A3)