Ion-acoustic double layers and solitary waves in a magnetized plasma consisting of warm ions and non-thermal electrons

A MKdV-KdV-ZK equation is derived describing the nonlinear behaviour of ion-acoustic waves in a magnetized plasma consisting of warm ions and non-thermal electrons valid near the points in the parameter space, where the coefficient of the nonlinear term in the corresponding KdV-ZK equation vanishes. This equation is used to obtain solitary wave solutions having profiles different from sech(2) or sech and also to obtain double layer solutions propagating at an arbitrary angle with the external magnetic field. The conditions for their existence are derived. The tanh method is applied in obtaining these solutions.