Fully nonlinear solitary waves in a dusty electronegative multispecies plasmas

Abstract

The formation and dynamics of fully nonlinear ion-acoustic solitary waves, which accompany electronegative plasmas composed of positive ions, two-negative ions, isothermal electrons, as well as a fraction of stationary charged (positive or negative) dust impurities are investigated. By using the hydrodynamic and Poisson equations, an energy-integral equation involving a Sagdeev pseudo-potential is derived. Using the latter, we have defined precisely the existence regions of the electrostatic localized pulses. The critical total negative ions concentration αc and critical second-negative ion density ratio νc thresholds, which indicate where the solitary pulses set in, have been determined for various regimes. Numerical calculations reveal that only supersonic pulses can exist. The total negative ions concentration, the second-to-total negative ions density ratio, electrons-to-positive ions temperature ratio, dust impurities concentration, positive-to-negative mass ratio, and Mach number have been investigated on the nonlinear wave profile. It is found that the total negative ion concentration as well as the dust particles concentration play the significant role in deciding the polarity of the propagating pulses. The results could be applied to investigate and predict the behavior of the nonlinear solitary structure in future laboratory plasma experiment having dusty electronegative multispecies plasmas as referred by Ichiki et al. [Phys. Plasmas 8, 4275 (2001)].