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of nonthermality of ions on solitons properties and in a two-temperature

dusty fluid.

Theskeletonof thisthesisisasfollows:
In chapter (2) the nonlinear dust-acoustic solitary waves (DASWs)

in an unmagnetized dusty plasma having electrons, nonthermal ions, hot

and cold dust grains have been investigated and the nonlinear Schrödinger

equation is obtained from the application of the derivative expansion per-
turbation theory. Chapter (3) is assigned to the nonlinear dust-acoustic

modulational instability for the plasma system considered in chapter (2).

In this model, numerical studies have been made using plasma parame-
ters close to those values correspond to Saturn F-rings. In chapter (4)

three-dimensional nonplanar unmagnetized dusty plasma system having

Boltzmann distributed electrons, nonthermal ions, cold and adiabatic hot
dust grains has been investigated. The 3D-CKP equation is derived using

the reductive perturbation method and its solution is obtained. The ef-

fects of plasma parameters on the wave phase velocity soliton amplitude
and width have been examined. Furthermore, the soliton profile forma-

tion is tested with the radial, axial and polar angle coordinates with time

increment.

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