Possibility of weakly charged nonlinear solitary dust clouds near the continuum threshold of dust population in a quasi-neutral dusty plasma

Considering the Boltzmann response of the plasma ions and electrons and ine rtial dynamics of the charged dust grains, the possibility of very weak com pressive soliton near the continuum limit of the dust population has been i nferred. It is concluded that the behaviour of such coherent structures cou ld be well described by the numerical analysis of the derived nonlinear cla ssical energy integral equation for bounded solutions. These seem to be hig her order dispersive structures within acoustic limit of the nonlinear turb ulence. It is observed that the dust density enhancement beyond the continu um threshold causes regular increment in width and amplitude of the soliton structures. It is found that the soliton amplitude sensitively depends on the massive impurity's population. These coherent structures could be visua lized as weakly charged solitary dust clouds of finite extension (similar t o plasma Debye length) within Boltzmann environment of plasma particles in their local surroundings. The seeding mechanism of such clouds may be attri buted to some plasma instabilities driven by either internal or external fr ee energy sources. Numerical analysis of the problem concludes that the exp erimental observations of such clouds could be possible in low density plas ma regime. It is deduced that for plasma density similar to 10(6) cm(-3) at temperatures of a few electron volts and for micron to 10 nm sized dust gr ains, the observation of such structures could be possible within wide rang e variability of the dust population density.