Dust-Acoustic Solitons in a Polarized Dusty Plasma With Nonthermal Ions

We theoretically investigate the effects of the nonthermal polarization force acting on dust grains in an inhomogeneous plasma containing Maxwellian electrons, nonthermal ions, and fluid negatively charged dust grains. The effects of this polarization force are significantly modified due to the presence of the nonthermal ions. In particular, an increase of the relative fraction of the nonthermal ions leads to a decrease of the polarization parameter. The modifications arising in the propagation of weak dust-acoustic (DA) solitary waves due to the presence of this nonthermal polarization force are then analyzed. As the magnitude of the polarization force increases, the energy carried by the DA soliton experiences a depletion.

I. Introduction

The physics of dusty plasma has gained much interest and rapid maturation during the last two decades. Their widespread occurrence in diverse environments [1]–[4] makes them as one of the best candidates for the understanding of the underlying physics of space and astrophysical observations, as well as laboratory experiments. In addition to electrons and ions, a dusty plasma contains highly charged and massive particulates [5]–[7]. The presence of dust grains can significantly alter the properties and behavior of a plasma in which they are immersed [4], [8]. It affects all kinds of plasma wave modes and, remarkably, gives rise to new, very low-frequency dust modes. The dust-acoustic wave (DAW) is one such new mode [9], peculiar to this system with the dust particles providing inertia and the pressure contributions for sustaining the wave, coming from both the lighter species (the electrons and the ions).