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Title: Measurements of spatially growing dust acoustic waves in a dc glow discharge plasma

Abstract

In this paper, an experiment is performed on dust acoustic waves in a dc glow discharge plasma. Stereoscopic particle image velocimetry (stereo-PIV) techniques are used to make measurements of the dust acoustic waves. These stereo-PIV measurements reveal the spatial growth of the waves over three to six wavelengths before reaching a saturated level. Experimental measurements are shown to agree with a simple model for spatially varying waves.

Authors:
 [1]
  1. Physics Department, Auburn University, Auburn, Alabama 36849-5311 (United States)
Publication Date:
OSTI Identifier:
20782727
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 4; Other Information: DOI: 10.1063/1.2193540; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DUSTS; GLOW DISCHARGES; ION ACOUSTIC WAVES; PARTICLES; PLASMA; PLASMA DIAGNOSTICS; SOUND WAVES; WAVELENGTHS

Citation Formats

Thomas, Edward Jr. Measurements of spatially growing dust acoustic waves in a dc glow discharge plasma. United States: N. p., 2006. Web. doi:10.1063/1.2193540.
Thomas, Edward Jr. Measurements of spatially growing dust acoustic waves in a dc glow discharge plasma. United States. doi:10.1063/1.2193540.
Thomas, Edward Jr. Sat . "Measurements of spatially growing dust acoustic waves in a dc glow discharge plasma". United States. doi:10.1063/1.2193540.
@article{osti_20782727,
title = {Measurements of spatially growing dust acoustic waves in a dc glow discharge plasma},
author = {Thomas, Edward Jr.},
abstractNote = {In this paper, an experiment is performed on dust acoustic waves in a dc glow discharge plasma. Stereoscopic particle image velocimetry (stereo-PIV) techniques are used to make measurements of the dust acoustic waves. These stereo-PIV measurements reveal the spatial growth of the waves over three to six wavelengths before reaching a saturated level. Experimental measurements are shown to agree with a simple model for spatially varying waves.},
doi = {10.1063/1.2193540},
journal = {Physics of Plasmas},
number = 4,
volume = 13,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}
  • 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 {mu}m/pixel. We performed experiments with different techniques of the wave excitation.more » 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 capacitor into a flat coil reeled around the discharge tube. The impulse of the axial magnetic field excited a perturbation. The perturbation had a character of discontinuity of the dust density and velocity. The perturbation was steepening and formed into a dust-acoustic shock. One more method of the wave excitation was developed that allowed to get two pulses. This gives us a possibility to investigate an interaction of waves excited in the dust component and a propagation of waves in a dusty plasma media with changeable dust density as well.« less
  • The experimental observation of the self–excited dust acoustic waves (DAWs) and its propagation characteristics in the absence and presence of a floating cylindrical object is investigated. The experiments are carried out in a direct current (DC) glow discharge dusty plasma in a background of argon gas. Dust particles are found levitated at the interface of plasma and cathode sheath region. The DAWs are spontaneously excited in the dust medium and found to propagate in the direction of ion drift (along the gravity) above a threshold discharge current at low pressure. Excitation of such a low frequency wave is a resultmore » of the ion–dust streaming instability in the dust cloud. Characteristics of the propagating dust acoustic wave get modified in the presence of a floating cylindrical object of radius larger than that of the dust Debye length. Instead of propagation in the vertical direction, the DAWs are found to propagate obliquely in the presence of the floating object (kept either vertically or horizontally). In addition, a horizontally aligned floating object forms a wave structure in the cone shaped dust cloud in the sheath region. Such changes in the propagation characteristics of DAWs are explained on the basis of modified potential (or electric field) distribution, which is a consequence of coupling of sheaths formed around the cylindrical object and the cathode.« less
  • In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.
  • An experimental investigation of dust acoustic (DA) waves in a dc glow discharge plasma is described. The glow discharge is formed between a 3 cm anode disk and the grounded walls of a 60 cm diameter vacuum chamber which is filled with nitrogen gas at a pressure of about 100 mTorr. Dust located on a tray in the chamber is attracted into the plasma where it is trapped electrostatically. The dust acoustic waves were produced by applying a modulation signal (5{endash}40 Hz) to the anode. The wavelength of the DA waves was measured from single frame video images of scatteredmore » light from the dust grains. The measured dispersion relation is compared with theoretical predictions. {copyright} {ital 1997 American Institute of Physics.}« less
  • Dust acoustic waves (DAWs) are spontaneously excited in dusty plasmas produced in dc and rf discharge plasmas over a wide range of plasma and dust conditions. A common feature of these plasmas is the presence of an ion drift relative to the dust, which is driven by an electric field, E{sub o} in the discharge. Using a three fluid model of the DAWs, including the zero order electric field and collisions of all species with the background neutral gas (pressure P{sub o}), DAW stability curves were obtained in the E{sub o}-P{sub o} plane, for various dust and wave parameters. Themore » (E{sub o},P{sub o}) data points from several experiments in which DAWs have been observed are also shown in comparison with the theoretical stability boundaries. This analysis supports the conclusion that the DAWs are excited by an ion-dust streaming instability.« less