Özet:
The formation of ion-acoustic solitons (IASs) in an unmagnetized plasma with negative ions has been investigated through the KdV equation in both the situations Q′(=mj/mi=negativetopositiveionmassratio) less and greater than one and the mKdV equation only for Q′> 1. The existence of both KdV and mKdV solitons has been established for α(=iontoelectrontemperatureratio)>β(=negativeiontoelectrontemperatureratio) and α< β, which is the new outcome of the current investigation. Furthermore, the existence of both compressive and rarefactive solitons for Q′> 1 and Q′< 1 has been demonstrated.