  We study the influence of ion beam and charged dust impurity on the
propagation of dust ion-acoustic (DIA) solitary wave (SW) in an unmagnetized
plasma consisting of Boltzmann distributed electrons, positive ions, positive
ion beam and negatively charged immobile dusts in a double plasma device. On
interacting with an ion beam, the solitary wave is bifurcated into a
compressive fast and a rarefactive slow beam mode, and appears along with the
primary wave. However, there exists a critical velocity of the beam beyond
which the amplitude of the fast solitary wave starts diminishing and
rarefactive slow beam mode propagates with growing amplitude. Whereas, the
presence of charged dust impurity in the plasma reduces this critical beam
velocity and a substantial modification in the phase velocity of the slow beam
mode is observed with increasing dust density. Furthermore, the nonlinear wave
velocity (Mach number) as well as the width of the compressive solitons are
measured for different beam velocity and dust density, and are compared with
those obtained from the K-dV equation. The experimental results are found in a
well agreement with the theoretical predictions.
