Obliquely propagating electron-acoustic solitary waves in plasma with nonthermal electrons

Viking Satellite observations have revealed solitary potential structures in the dayside auroral zone. A theoretical investigation is carried out for understanding the properties of obliquely propagating electron-acoustic solitary waves (EASWs) in an magnetized collisionless plasma consisting of a cold electron fluid and non-thermal hot electrons obeying a non-thermal distribution, and stationary ions. The reductive perturbation method has been employed to derive the Zakharov-Kuznetsov (ZK) equation for small but finite amplitude electrostatic waves. It is found that the present plasma model supports rarefactive EASWs solitons. The effects of the external magnetic field and the obliqueness are found to significantly change the basic properties (viz. the amplitude and the width) of the EASWs. The present investigation can be of relevance to the electrostatic solitary structures observed in various space plasma environments (viz. the cusp of the terrestrial magnetosphere, the geomagnetic tail, the auroral regions, etc.).