Effect of dust charge polarization on the propagation characteristics of nonlinear Dust-acoustic solitons and double layers in superthermal un-magnetized complex plasma

Abstract

The propagation characteristics of solitons and double layers associated with the dust-acoustic waves (DAWs) are studied in superthermal un-magnetized plasma through solitary and double layer solutions of the nonlinear Korteweg–de Vries (KdV) and the modified Korteweg–de Vries (mKdV) equations, respectively. The plasma constituents are superthermal electrons, superthermal ions, and dust particles. The electrons and ions follow the generalized Lorentzian velocity distribution while the dust particles are considered inertial and bear the charge polarization effect. In the small amplitude limit, we found that the phase velocity of the DAWs varies inversely with the polarization force. The effects of the polarization force and superthermality index on the properties of the solitons and double layer structures are also traced in the small but finite amplitude limit. It is found that the strong superthermality and dust charge polarization decrease the soliton’s energy. A study of the phase portrait is also carried out to investigate the propagation features of the solitary waves through parametric dependence of the configured plasma. It is found that for a selected set of configured parameters, the plasma system supports only rarefactive solitons. Furthermore, the amplitude of double layers has been observed to vary inversely with both the superthermality and the polarization force.