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In dusty plasmas, overlapping Debye spheres around dust grains could produce an attractive force between them. Its effects on static structures of two-dimensional (2D) dusty plasmas are studied here by using molecular dynamics simulations. Results, in terms of the equilibrium radial distribution function, are compared with those deduced from purely repulsive Debye–Huckel or Yukawa potential for different Coulomb-coupling and screening parameters. The effect of the attractive force is found quite noticeable for usual experimental conditions, and becomes more pronounced for larger screening parameter κ. In particular, it is observed that for large κ the attractive force is dominant, and dust grains tend to aggregate and form patterns with scattering voids.

Laser-excited waves in a two-dimensional dust plasma crystal have been observed experimentally in a parallel plate rf discharge. The measured dispersion relation is compared with theoretical models. Agreement is found with dust lattice waves, whereas deviations from dust acoustic waves exist. From the dispersion relation of a dust lattice wave the screening of the particles in the rf sheath is determined.

The chaotic state of the classical Pierce diode is studied using a particle-in-cell computer simulation. The dynamics of the chaotic state is analyzed by estimating ergodic measures of the reconstructed attractor that refine and extend previously reported results [Matsumoto et al., Phys. Plasmas 3 (1996) 177]. The chaos control algorithm suggested by Ott, Grebogi, and Yorke is systematically applied to stabilize periodic orbits up to periodicity four. This demonstrates successful chaos control in a plasma, i.e., a many particle system with long range collective Coulomb interaction.

An experimental method for the measurement of the shielding of dust particles in the sheath of an rf plasma based on the excitation of coupled oscillations of a linear particle arrangement is presented. With the measured screening strength the solid-liquid phase transition of the plasma crystal is analysed.

Low-frequency ( ω ⪡ ω pi ) plasma oscillations in the transition regime between the high and the low current mode of a thermionic hot-cathode discharge are investigated experimentally. This type of current oscillation often shows chaotic dynamics. The current oscillations are related to nonlinear short wavelength potential structures which are identified as ion bunches formed by a fluctuating ionization front. These ion bunches are separated by ion holes and move at ion thermal speed rather than ion acoustic speed. By entering the negative space charge region of the cathode sheath, the ion bunches trigger electron current fluctuations that provide the required feedback mechanism for the observed wave train formation.

The oscillations of the ion sheath around a negatively biased grid in dp machines are studied experimentally and compared with PIC simulations. It is argued that for asymmetric densities in the source and target chamber the ion sheath on the low density side becomes unstable to virtual anode oscillations which act as a driver for the ion bounce oscillations in the sheath. Resonant coupling with the ion plasma frequency at the sheath edge of the source plasma is found. Subharmonic coupling with potential relaxation oscillations may explain the period doubling route to chaos found in such systems.

Large dust grains ( r p =10 μ m) are found to form hexagonal Coulomb lattices with an interparticle distance of R p =880 μ m in the sheath of an argon rf discharge. The charge on the particle is measured from its resonant response to an external periodic force. The charge is found to be -200000 e .

The dynamics of interacting self-excited and driven ionization waves is studied experimentally. The transition from quasiperiodicity to mode-locking shows a phenomenon known as periodic pulling. As dynamical model, the forced van der Pol system is established. Its theoretical predictions are fully confirmed by experiment.