Nonlinear "oscilliton" structures features a low-frequency(LF) solitary envelope, the amplitude of which is modulatedviolently by superimposed high-frequency (HF) oscillations. We have studiedthe charge non-neutrality effects on the excitation of electrostaticion-acoustic (IA) oscillitons. A two-fluid, warm plasma model isemployed, and a set of nonlinear self-similar equations is solved ina cylindrical geometry. Under charge-neutrality conditions, threeconventional IA structures (namely, sinusoidal, sawtooth, andspicky/bipolar) are obtained. By contrast, under chargenon-neutrality conditions, oscilliton structures are excited, wherethe LF envelope is in the sound-wave (SW) mode, while the HFingredients include the IA mode and the ion-Langmiur (IL) mode. Theamplitudes of the SW wave are violently modulated by the IAoscillations, whereas the upward sides of the IA amplitudes aremodulated by the IL oscillations of smaller amplitudes, and thedownward sides are modulated by hybrid IA/IL oscillations. Thenonlinear oscillitons are found to be dependent not only upon the inputparameters (e.g., the Mach number, the Debye length, and the initialtemperature of particles), but on initial conditions as well.
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