Ion-acoustic solitary waves and shocks in a collisional dusty negative-ion plasma

We study the effects of ion-dust collisions and ion kinematic viscosities on the linear ion-acoustic instability as well as the nonlinear propagation of small-amplitude solitary waves and shocks (SWS) in a negative-ion plasma with immobile charged dusts. The existence of two linear ion modes, namely the "fast" and "slow" waves, is shown, and their properties are analyzed in the collisional negative-ion plasma. Using the standard reductive perturbation technique, we derive a modified Korteweg-de Vries-Burger (KdVB) equation which describes the evolution of small-amplitude SWS. The profiles of the latter are numerically examined with parameters relevant for laboratory and space plasmas where charged dusts may be positively or negatively charged. It is found that negative-ion plasmas containing positively charged dusts support the propagation of SWS with negative potential. However, the perturbations with both positive and negative potentials may exist when dusts are negatively charged. The results may be useful for the excitation of SWS in laboratory negative-ion plasmas as well as for observation in space plasmas where charged dusts may be positively or negatively charged.