V. M. Torchinsky

Mechanism of dust-acoustic instability in a direct current glow discharge plasma

An observation of low frequency waves spontaneously excited in a dc glow discharge dusty plasma is reported. To analyze possible reasons for the instability observed, a linear dispersion relation which takes into account collisions with neutrals, dust grain charge variations, ion drift, and forces acting on dust particles is derived. Numerical analysis of the dispersion relation shows that the observed instability is the result of dust charge variations in the presence of external charge-dependent forces together with the ion drift effect.

CRYSTALLINE STRUCTURES OF STRONGLY COUPLED DUSTY PLASMAS IN DC GLOW DISCHARGE STRATA

Abstract Strongly coupled dusty plasmas are formed by suspending micron-sized dust particles in strata of a dc glow neon discharge. We have observed for the first time an ordered structure of the negatively charged particles trapped in the strata region. Image analysis reveals the crystalline structure, which is consistent with a large value of the Coulomb coupling parameter.

Plasma Crystals and Liquids in DC Glow Discharge

Publisher Summary This chapter presents the results of experimental investigations of dusty plasma structures formed in striations of a positive column of the DC low-pressure glow discharge. Depending upon a relation between forces acting on dust particles, (gravity, electrical, ion drag) different types of dusty plasma formations are observed—plasma crystals, structures with a short-distance order, and structures with a convective movement of dust grains. The molecular dynamics simulation performed shows a good agreement with the experimental data.

Dusty plasma structures under the external influences

Expeiments on different external influences on the dusty plama structures in the dc glow discharge are presented. The possibility of their application for diagnostic purposes is shown. Gas dynamic influence on the dusty plasma structures was considered for the first time. It was used for the excitation of nonlinear dust acoustic waves.

Dust Waves Excited in a DC Glow Discharge Plasma

We present a review of experimental studies to excite nonlinear dust waves in a dc glow discharge plasma. The experiments were performed in a vertically positioned glass tube filled with neon and the stratified glow discharge with cold electrodes was created inside it. Dust particles were injected into a plasma and formed ordered structures in the striations. The dust grains were illuminated with a laser sheet and the scattered light was registered with a high‐speed digital videocamera with the frame rate of 1000 fps and spatial resolution of 20 μm/pixel. We performed experiments with different techniques of the wave excitation. First, we used the gas‐dynamic impact to move the dusty plasma structure with respect to their trap. In this case a large‐amplitude wave with two compressional regions separated by a rarefaction was generated. The second wave excitation method was the application of an electromagnetic impulse to the dusty plasma structure. The impulse was created by the discharge of a high‐voltage...

Dusty plasmas in a dc glow discharge

The striations proved to be a very useful tool to study various phenomena taking place in complex plasmas. In this work we present results of observations within a wide range of formations from an ordinary chain of several charged dust grains up to complex structures consisting of regions with different dusty plasma states. Plasma crystals, liquid‐like structures with a short‐range order and with a convective motion of dust particles, a development of dust waves have been studied at different plasma conditions and with spherical dust particles varying in size from 1.9 μm up to 63 μm. Experiments with 300 μm long cylindrical dust grains discovered the formation of the ordered structure similar to the liquid crystal.