Analytical solutions and parametric studies of the Schamel equation for two different ion-acoustic waves in plasmas

A numerical investigation of the properties of two different ion-acoustic solitons has been performed by using analytical solutions of the Schamel equation. A new type of the analytical solution of the Schamel equation that describes soliton propagation with a negative phase velocity has been found for the first time. This new type of the solution has been applied to investigate the physical properties of two different plasmas and to understand the effect of nonextensivity and the effect of trapped electrons on ion-acoustic waves in a superthermal plasma. It is shown that the soliton amplitude and width depend on the nonextensivity parameter, superthermality of the electron distribution, and characteristic trapping parameter.