Effect of the presence of excess superthermal hot electrons on electron-acoustic solitary waves in auroral zone plasma

A theoretical investigation is carried out for the nonlinear properties of small amplitude electron acoustic solitary waves (EAWs) in an unmagnetized collisionless plasma consisting of a cold electron fluid and hot electrons obeying κ velocity distribution, and stationary ions. The Korteweg de Vries (KdV) equation that contains the lowest-order nonlinearity and dispersion is derived from the lowest order of perturbation and a linear inhomogeneous (KdV-type) equation that accounts for the higher-order nonlinearity and dispersion is obtained. A stationary solution for equations resulting from higher-order perturbation theory has been found using the renormalization method. The effects of the spectral index κ and the higher-order corrections are found to significantly change the properties (viz. the amplitude, width, electric field ) of the EASWs. A comparison with the Viking Satellite observations in the dayside auroral zone are also discussed.