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A simple practical approach to describe transverse (shear) waves in strongly-coupled Yukawa fluids is presented. Theoretical dispersion curves, based on hydrodynamic consideration, are shown to compare favorably with existing numerical results for plasma-related systems in the long-wavelength regime. The existence of a minimum wave number below which shear waves cannot propagate and its magnitude are properly accounted in the approach. The relevance of the approach beyond plasma-related Yukawa fluids is demonstrated by using experimental data on transverse excitations in liquid metals Fe, Cu, and Zn, obtained from inelastic x-ray scattering. Some potentially important relations, scalings, and quasi-universalities are discussed. The results should be interesting for a broad community in chemical physics, materials physics, physics of fluids and glassy state, complex (dusty) plasmas, and soft matter. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations have been performed to investigate in detail collective modes spectra of two-dimensional Coulomb fluids in a wide range of coupling. The obtained dispersion relations are compared with theoretical approaches based on quasi-crystalline approximation, also known as the quasi-localized charge approximation, in the plasma-related context. An overall satisfactory agreement between theory and simulations is documented for the longitudinal mode at moderate coupling and in the long-wavelength domain at strong coupling. For the transverse mode, satisfactory agreement in the long-wavelength domain is only reached at very strong coupling, when the cutoff wave-number below which shear waves cannot propagate becomes small. The dependence of the cutoff wave-number for shear waves on the coupling parameter is obtained. [ABSTRACT FROM AUTHOR]

The motion and the equilibrium position of cylindrical particles in a radio-frequency plasma have been interpreted by dipole and quadrupole interaction in two experimental situations. Particles levitating in steady state are aligned either horizontal or vertical in accordance with the theory. However, particles have been observed tilted w.r.t, the vertical when acquiring a horizontal velocity from sailing in the ion stream. Particles in defect of charge fall on the lower electrode, mainly vertically, and build complex 'woody' structures. Index Terms--Complex plasmas, plasmas, plasma sheaths, powders.

New data of the electronic properties of liquid helium and liquid neon are discussed with respect to their relevance for the initiation of electric breakdown. It is concluded that under ideal conditions the cathode plays a decisive role in the initiation of the breakdown process. It is speculated that a Townsend type breakdown mechanism is absent in the liquid phase of these elements. Index Terms--Liquid helium, breakdown, liquid neon, delocalized electrons, heat of vaporization, Townsend process, electron multiplication, radiation.