  The propagation of nonlinear electron- acoustic waves (EAWs) in an
unmagnetized collision- less plasma system consisting of a cold electron fluid,
superthermal hot electrons and stationary ions is investigated. A reductive
perturbation method is employed to obtain a modified Korteweg-de Vries (mKdV)
equa- tion for the first-order potential. The small amplitude electron-acoustic
solitary wave, e.g., soliton and dou- ble layer (DL) solutions are presented,
and the effects of superthermal electrons on the nature of the solitons are
also discussed. But the results shows that the weak stationary EA DLs cannot be
supported by the present model.

Plasma Physics