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Title: Dust and dust-void structures in the presence of the ion diffusion

Abstract

The structure of the dust void boundary and the distribution of the dust and plasma parameters in the dust structure bordering the void is analyzed taking into account effects of dissipation due to the ion diffusion on plasma neutrals. Numerical calculations demonstrate various sorts of diffusive dust void structures; the possibility of singularities in the balance equations caused by the diffusion process inside the dust structures is investigated. These singularities can be responsible for a new type of shock-like structures.

Authors:
 [1];  [2];  [3]
  1. General Physics Institute, Russian Academy of Science, Vavilova St. 38, 117942 Moscow (Russian Federation)
  2. School of Physics, University of Sydney, New South Wales 2006 (Australia)
  3. Max-Planck-Institut fuer extraterrrestrische Physik, D-85740 Garching (Germany)
Publication Date:
OSTI Identifier:
20726753
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 799; Journal Issue: 1; Conference: 4. international conference on the physics of dusty plasmas, Orleans (France), 13-17 Jun 2005; Other Information: DOI: 10.1063/1.2134605; (c) 2005 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; DIFFUSION; DISTRIBUTION; DUSTS; IONS; PLASMA; SINGULARITY; SOLIDS; VOIDS

Citation Formats

Tsytovich, V.N., Vladimirov, S.V., and Morfill, G.E. Dust and dust-void structures in the presence of the ion diffusion. United States: N. p., 2005. Web. doi:10.1063/1.2134605.
Tsytovich, V.N., Vladimirov, S.V., & Morfill, G.E. Dust and dust-void structures in the presence of the ion diffusion. United States. doi:10.1063/1.2134605.
Tsytovich, V.N., Vladimirov, S.V., and Morfill, G.E. Mon . "Dust and dust-void structures in the presence of the ion diffusion". United States. doi:10.1063/1.2134605.
@article{osti_20726753,
title = {Dust and dust-void structures in the presence of the ion diffusion},
author = {Tsytovich, V.N. and Vladimirov, S.V. and Morfill, G.E.},
abstractNote = {The structure of the dust void boundary and the distribution of the dust and plasma parameters in the dust structure bordering the void is analyzed taking into account effects of dissipation due to the ion diffusion on plasma neutrals. Numerical calculations demonstrate various sorts of diffusive dust void structures; the possibility of singularities in the balance equations caused by the diffusion process inside the dust structures is investigated. These singularities can be responsible for a new type of shock-like structures.},
doi = {10.1063/1.2134605},
journal = {AIP Conference Proceedings},
number = 1,
volume = 799,
place = {United States},
year = {Mon Oct 31 00:00:00 EST 2005},
month = {Mon Oct 31 00:00:00 EST 2005}
}
  • A dust void is a dust-free region inside the dust cloud that often develops for conditions relevant to plasma processing discharges and complex plasma experiments. A distinctive feature of the void is a sharp boundary between the dust and dust-free regions; this is manifested especially clear when dissipation in the plasma is small and discontinuity of the dust number density appear. Here, the structure of the dust void boundary and the distribution of the dust and plasma parameters in the dust structure bordering the void is analyzed taking into account effects of dissipation due to the ion diffusion on plasmamore » neutrals. The sharp boundary between the dust and void regions exists also in the presence of the ion diffusion; however, only derivatives of the dust density, dust charge, electron density and electric field are discontinuous at the void boundaries, while the functions themselves as well as derivatives of the ion drift velocity and the ion density are continuous. Numerical calculations demonstrate various sorts of diffusive dust void structures; the possibility of singularities in the balance equations caused by the diffusion process inside the dust structures is investigated. These singularities can be responsible for a new type of shocklike structures. Other structures are typically self-organized to eliminate the singularities. Numerical computations in this case demonstrate a set of thin dust layers separated by high density thin dust clouds similar to the multiple-layer dust structures observed in the laboratory and in the upper ionosphere. The possibility for existence of a few equilibrium positions of the void boundary is discussed.« less
  • The Sagdeev potential technique has been employed to study the dust ion acoustic solitary waves and double layers in an unmagnetized collisionless dusty plasma consisting of negatively charged static dust grains, adiabatic warm ions, isothermally distributed electrons, and positrons. A computational scheme has been developed to draw the qualitatively different compositional parameter spaces or existence domains showing the nature of existence of different solitary structures with respect to any parameter of the present plasma system. The present system supports both positive and negative potential double layers. The negative potential double layer always restricts the occurrence of negative potential solitary waves,more » i.e., any sequence of negative potential solitary waves having monotonically increasing amplitude converges to a negative potential double layer. However, there exists a parameter regime for which the positive potential double layer is unable to restrict the occurrence of positive potential solitary waves. As a result, in this region of the parameter space, there exist solitary waves after the formation of positive potential double layer, i.e., positive potential supersolitons have been observed.« less
  • Experiments demonstrate a variety of dust void structures such as stable or unstable voids, global 'heatbeat' modes of oscillations of voids, dust voids in the center of the chamber or near its walls. Theory shows that a dust void generally results from the balance of the electrostatic and the plasma (such as the ion drag) forces acting on a dust particle. Here, the stability theory of a 'virtual' void is developed and its behavior is modeled. It is shown that sequences of stable and unstable void sizes can exist. The dynamics of dust in a plasma follows these stability characteristicsmore » leading to various stable and/or unstable dust void structures.« less
  • A systematic theoretical investigation has been carried out on the role of dust charging dynamics on the nature and stability of DIA (Dust Ion Acoustic) mode in complex plasma. The study has been made for both linear and non-linear scale regime of DIA mode. The observed results have been characterized in terms of background plasma responses towards dust surface responsible for dust charge fluctuation, invoking important dusty plasma parameters, especially the ion flow speed and dust size. The linear analyses confirm the nature of instability in DIA mode in presence of dust charge fluctuation. The instability shows a damping ofmore » DIA mode in subsonic flow regime followed by a gradual growth in instability in supersonic limit of ion flow. The strength of non-linearity and their existence domain is found to be driven by different dusty plasma parameters. As dust is ubiquitous in interstellar medium with plasma background, the study also addresses the possible effect of dust charging dynamics in gravito-electrostatic characterization and the stability of dust molecular clouds especially in proto-planetary disc. The observations are influential and interesting towards the understanding of dust settling mechanism and formation of dust environments in different regions in space.« less
  • The nonuniform polarization charging effects due to the ion flow on the ion-dust elastic collision process is investigated in the presence of ion drift. The Born analysis is considered to obtain the scattering amplitude and cross section as a function of the momentum transfer, Mach number, and Debye length. The result shows that the nonuniform charging effects significantly enhance the differential scattering cross section for backward-scattering directions. It is also found that the nonuniform charging effects are significant for large momentum transfers.