Effects of nonthermal electrons and positrons on the characteristics of ion-acoustic cnoidal wave in electron-positron-ion plasma

Effects of nonthermal electrons and positrons on the nature of ion acoustic cnoidal wave in the plasma contains ions, positrons, and electrons are investigated. Reductive perturbation method was employed to solve the fluid dynamic equations with appropriate boundary condition and derivation of Korteweg-de Vries (KdV) equation for nonlinear periodic ion acoustic wave. Sagdeev potential was extracted and the condition of plasma nonthermality on the formation of solitary and cnoidal ion acoustic wave has been discussed in detail. Results show that for all magnitudes of electrons (positrons) nonthermal coefficient, αe (αp) ion acoustic wave may generate in plasma medium. With increasing both αe and αp the amplitude of cnoidal ion acoustic wave increases. The wavelength of ion acoustic wave increases with increasing αp and decreases with increasing αe.