Rarefactive ion-acoustic electrostatic solitary structures in nonthermal plasmas
The Abdus Salam International Centre for Theoretical Physics,
P.O. Box 586, Trieste, Italy
Corresponding author: a firstname.lastname@example.org
Published online: 15 July 2000
An investigation has been made of ion-acoustic solitary waves in an unmagnetized nonthermal plasma whose constituents are an inertial ion fluid and nonthermally distributed electrons. The properties of stationary solitary structures are briefly studied by the pseudo-potential approach, which is valid for arbitrary amplitude waves, and by the reductive perturbation method which is valid for small but finite amplitude limit. The time evolution of both compressive and rarefactive solitary waves, which are found to coexist in this nonthermal plasma model, is also examined by solving numerically the full set of fluid equations. The temporal behaviour of positive (compressive) solitary waves is found to be typical, i.e., the positive initial disturbance breaks up into a series of solitary waves with the largest in front. However, the behaviour of negative (rarefactive) solitary waves is quite different. These waves appear to be unstable and produce positive solitary waves at a later time. The relevancy of this investigation to observations in the magnetosphere of density depressions is briefly pointed out.
PACS: 52.35.Fp – Electrostatic waves and oscillations (e.g., ion-acoustic waves) / 52.35.Sb – Solitons; BGK modes / 52.35.Mw – Nonlinear waves and nonlinear wave propagation (including parametric effects, mode coupling, ponderomotive effects, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000