Nonlinear dust acoustic waves in inhomogeneous four-component dusty plasma with opposite charge polarity dust grains

The reductive perturbation technique is employed to investigate the propagation properties of nonlinear dust acoustic (DA) waves in a four-component inhomogeneous dusty plasma (4CIDP). The 4CIDP consists of both positive-and negative-charge dust grains, characterized by different mass, temperature, and density, in addition to a background of Maxwellian electrons and ions. The inhomogeneity caused by nonuniform equilibrium values of particle densities, fluid velocities, and electrostatic potential leads to a significant modification to the nature of nonlinear DA solitary waves. It is found that this model reveals two DA wave velocities, one slow, lambda(s), and the other is fast, lambda(f). The nonlinear wave evolution is governed by a modified Kortweg-de Vries equation, whose coefficients are space dependent. Both the two soliton types; compressive and rarefactive are allowed corresponding to lambda(s). However, only compressive soliton is created corresponding to lambda(f). The numerical investigations illustrate the dependence of the soliton amplitude, width, and velocity on the plasma inhomogeneities in each case. The relevance of these theoretical results with 4CIDPs observed in a multi-component plasma configurations in the polar mesosphere is discussed. (C) 2013 AIP Publishing LLC.