arXiv subjects

V. Nosenko

Publications and source records attributed to V. Nosenko.

23 records · Page 2Linked to original sources

arXiv2011

Direct experimental measurement of the speed-stress relation for dislocations in a plasma crystal

The speed-stress relation for gliding edge dislocations was experimentally measured for the first time. The experimental system used, a two-dimensional plasma crystal, allowed observation of individual dislocations at the "atomistic" level and in real time. At low applied stress dislocations moved subsonically, at higher stress their speed abruptly increased to 1.9 times the speed of shear waves, then slowly grew with stress. There is evidence that immediately after nucleation dislocations can move faster than pressure waves.

cond-mat.soft↗

arXiv2010

Direct observation of mode-coupling instability in two-dimensional plasma crystals

Dedicated experiments on melting of 2D plasma crystals were carried out. The melting was always accompanied by spontaneous growth of the particle kinetic energy, suggesting a universal plasma-driven mechanism underlying the process. By measuring three principal dust-lattice (DL) wave modes simultaneously, it is unambiguously demonstrated that the melting occurs due to the resonance coupling between two of the DL modes. The variation of the wave modes with the experimental conditions, including the emergence of the resonant (hybrid) branch, reveals exceptionally good agreement with the theory of mode-coupling instability.

physics.plasm-ph↗

arXiv2009

First direct measurement of optical phonons in 2D plasma crystals

Spectra of phonons with out-of-plane polarization were studied experimentally in a 2D plasma crystal. The dispersion relation was directly measured for the first time using a novel method of particle imaging. The out-of-plane mode was proven to have negative optical dispersion, comparison with theory showed good agreement. The effect of the plasma wakes on the dispersion relation is briefly discussed.

physics.plasm-ph↗

arXiv2007

Supersonic dislocations observed in a plasma crystal

Experimental results on the dislocation dynamics in a two-dimensional plasma crystal are presented. Edge dislocations were created in pairs in lattice locations where the internal shear stress exceeded a threshold and then moved apart in the glide plane at a speed higher than the sound speed of shear waves, $C_T$. The experimental system, a plasma crystal, allowed observation of this process at an atomistic (kinetic) level. The early stage of this process is identified as a stacking fault. At a later stage, supersonically moving dislocations generated shear-wave Mach cones.

cond-mat.soft↗

arXiv2005

Shear Flows and Shear Viscosity in a Two-Dimensional Yukawa System (Dusty Plasma)

The shear viscosity of a two-dimensional liquid-state dusty plasma was measured experimentally. A monolayer of highly charged polymer microspheres, with a Yukawa interaction, was suspended in a plasma sheath. Two counter-propagating Ar laser beams pushed the particles, causing shear-induced melting of the monolayer and a shear flow in a planar Couette configuration. By fitting the particle velocity profiles in the shear flow to a Navier-Stokes model, the kinematic viscosity was calculated; it was of order 1 mm^2/s, depending on the monolayer's parameters and shear stress applied.

cond-mat.soft↗