A broad-spectrum self-excited dust density wave is experimentally studied in a vertically extended nanodusty plasma consisting of in situ grown carbonaceous nanometer sized particles. The nanodusty plasma having high particle density (of the order of 10^12-10^13 m^(-3)) is created with vertical extension up to (40+-0.1) cm and radial extension up to (5+-0.1) cm. The propagation of the self-excited dust density wave under strong Havnes effect is examined over a large axial distance (19+-0.1) cm. Time-resolved Hilbert transformation and Fast Fourier transformation techniques are used to study the spatiotemporal evolution of frequency and wave numbers along three directions from the dust void viz. axial, radial and oblique. The propagation is found to be inhomogeneous throughout the dust cloud. The phase velocity of the wave is estimated to be quite low and decreasing along the direction of propagation. This effect is attributed to the strong reduction of particle charge due to a high Havnes parameter along the propagation direction. By the estimation of average particle charge, ion density and the finite electric field throughout the nanodust cloud, a quantitative analysis of the void formation in nanodusty plasma is presented. New insights are also made regarding wave merging phenomena using time-resolved Hilbert transformation.

A large volume 3D dust cloud containing in situ grown nanometer-sized particles is produced in a newly developed versatile table-top experimental device. Carbonaceous nanoparticles having almost uniform size throughout the dust cloud are grown using capacitively coupled rf discharge in Ar–C2H2 gas mixture with a low precursor gas flow rate (∼2 sccm) and minimal rf power (∼1 W). The vertical and radial extensions of the dust cloud are 40 cm and 5 cm, respectively. The pure Ar plasma in the setup is characterized by measuring the discharge parameters as well as plasma parameters under different discharge conditions. The average particle size and its temporal growth profile are determined by analyzing the scanning electron microscope images of the particles. The dust density measured using the laser extinction method is found to be of the order of 1016–1012 m−3 for the discharge duration of 2–10 min. A spontaneous dust density wave is also observed in the dust cloud.

A pair of counter-rotating symmetric vortices has been observed in the wake behind a stationary obstacle (dust void) in a flowing dusty plasma. A strongly coupled dusty plasma flow with controllable velocity is generated and directed toward the void in a novel experiment. In the unsteady laminar flow regime, the curl of the fluid flow velocity along the boundary layer of the void generates the vortex pair behind the void. Particle image velocimetry analysis of high speed image data clearly depicts the flow pattern and the vorticities. The shear viscosity of the dusty plasma fluid along with the experimental parameters is considered to obtain the Reynolds number range for the evolution of the vortices. Molecular dynamics simulation is also performed to support the experimental observation.

A void is produced in a strongly coupled dusty plasma by inserting a cylindrical pin (∼0.1 mm diameter) into a radiofrequency discharge argon plasma. The pin is biased externally below the plasma potential to generate the dust void. The Debye sheath model is used to obtain the sheath potential profile and hence to estimate the electric field around the pin. The electric field force and the ion drag force on the dust particles are estimated and their balance accounts well for the maintenance of the size of the void. The effects of neutral density as well as dust density on the void size are studied.