Coherent scattering of electromagnetic waves by selforganized dust structures: Degree of coherence
Abstract
It is demonstrated explicitly that the scattering of electromagnetic waves by dust structures can be strongly enhanced as compared to incoherent scattering by random electrons. If the size of the dust structure is much less than the wavelength of the incident radiation, the scattering is coherent. In this case, the scattering is proportional to the square of the total number of electrons in the structure. In the opposite limit, the scattering is incoherent being proportional to the total number of electrons in the structure. The factor describing the degree of coherency is calculated numerically for several models of selforganized structures. It is demonstrated in general way that for sudden heating of electrons, the factor of coherency in scattering by structures can decrease by several orders of magnitude with subsequent increase after the heating is switched off. In laboratory dusty plasmas, the coherent scattering is proposed for diagnostics of universal structuring instability and as a probe for determining the properties typical for selforganized nature of structures that are observed in recent experiments.
 Authors:
 A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilova str. 38, Moscow 119991 (Russian Federation)
 (Germany)
 (Russian Federation)
 Publication Date:
 OSTI Identifier:
 22408162
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COHERENT SCATTERING; DUSTS; ELECTROMAGNETIC RADIATION; ELECTRONS; HEATING; INCOHERENT SCATTERING; PLASMA; WAVELENGTHS
Citation Formats
Tsytovich, Vadim, Email: tsyto@mpe.mpg.de, Max Planck Institute for Extraterrestrial Physics, Garching, Guseinzade, Namik, Ignatov, Alexander, and Medicobiologic Faculty, Pirogov Russian National Research Medical University, Moscow. Coherent scattering of electromagnetic waves by selforganized dust structures: Degree of coherence. United States: N. p., 2015.
Web. doi:10.1063/1.4908279.
Tsytovich, Vadim, Email: tsyto@mpe.mpg.de, Max Planck Institute for Extraterrestrial Physics, Garching, Guseinzade, Namik, Ignatov, Alexander, & Medicobiologic Faculty, Pirogov Russian National Research Medical University, Moscow. Coherent scattering of electromagnetic waves by selforganized dust structures: Degree of coherence. United States. doi:10.1063/1.4908279.
Tsytovich, Vadim, Email: tsyto@mpe.mpg.de, Max Planck Institute for Extraterrestrial Physics, Garching, Guseinzade, Namik, Ignatov, Alexander, and Medicobiologic Faculty, Pirogov Russian National Research Medical University, Moscow. 2015.
"Coherent scattering of electromagnetic waves by selforganized dust structures: Degree of coherence". United States.
doi:10.1063/1.4908279.
@article{osti_22408162,
title = {Coherent scattering of electromagnetic waves by selforganized dust structures: Degree of coherence},
author = {Tsytovich, Vadim, Email: tsyto@mpe.mpg.de and Max Planck Institute for Extraterrestrial Physics, Garching and Guseinzade, Namik and Ignatov, Alexander and Medicobiologic Faculty, Pirogov Russian National Research Medical University, Moscow},
abstractNote = {It is demonstrated explicitly that the scattering of electromagnetic waves by dust structures can be strongly enhanced as compared to incoherent scattering by random electrons. If the size of the dust structure is much less than the wavelength of the incident radiation, the scattering is coherent. In this case, the scattering is proportional to the square of the total number of electrons in the structure. In the opposite limit, the scattering is incoherent being proportional to the total number of electrons in the structure. The factor describing the degree of coherency is calculated numerically for several models of selforganized structures. It is demonstrated in general way that for sudden heating of electrons, the factor of coherency in scattering by structures can decrease by several orders of magnitude with subsequent increase after the heating is switched off. In laboratory dusty plasmas, the coherent scattering is proposed for diagnostics of universal structuring instability and as a probe for determining the properties typical for selforganized nature of structures that are observed in recent experiments.},
doi = {10.1063/1.4908279},
journal = {Physics of Plasmas},
number = 2,
volume = 22,
place = {United States},
year = 2015,
month = 2
}

Dust structuring is a natural and universal process in complex plasmas. The scattering of electromagnetic waves by dust structures is governed by the factor of coherency, i.e., the total number of coherent electrons in a single structure. In the present paper, we consider how the factor of coherency changes due to additional pulse electron heating and show that it obeys a hysteresis. After the end of the pulse heating, the scattering intensity differs substantially from that before heating. There are three necessary conditions for scattering hysteresis: first, the radiation wavelength should be larger than the pattern (structure) size; second, themore »

Theory of dust selforganized convection in cylindrical discharges. I. The model and stationary nonlinear dust structures
The convection of dust particles in a plasma is related to the spatial gradients of dust charge distributions existing due to different plasma conditions in different parts of dusty structures. For many experiments, the convection appears as a result of convective perturbations of basic nonlinear selforganized states of the dust structures. Here, the set of nonlinear equations is derived suitable for the study of basic stationary dust structures as well as their convective perturbations. On its basis, the stationary nonlinear states of selforganized cylindrical dusty structures in a plasma are investigated. It is demonstrated that there is the broad rangemore » 
Theory of dust selforganized convection in cylindrical discharges. II. Dust convective structures
The convection of dust particles in a plasma is related to the spatial gradients of dust charge distributions existing due to different plasma conditions in different parts of dusty structures. Here, the set of nonlinear equations is derived to describe the dust convective structures appearing as perturbations of the basic nonlinear structures obtained in Part I. On its basis, various cases of the dust convection in cylindrical dusty structures in a plasma are obtained. It is demonstrated that there is the broad range of plasma and dust parameters where the selforganized dust convection exist. 
Nonlinear equilibrium spherical dust structures I: Basic equations and criterion for the existence of selforganized structures
Basic equations for dust structures are formulated that account for the balance of the forces, plasma fluxes, and grain charges with allowance for nonlinearity in the screening of individual grains and possible violation of quasineutrality due to the interaction of collective fields with plasma fluxes. A theory of nonlinear drag forces exerted by plasma fluxes on dust grains is developed for moderate drift flux velocities, higher than the mean ion thermal velocity but much lower than the acoustic speed. It is shown that equilibrium dust structures have finite sizes and negative charges and that they can exist only in amore » 
Selforganized coherent bursts of stimulated Raman scattering and speckle interaction in multispeckled laser beams
Nonlinear physics governing the kinetic behavior of stimulated Raman scattering (SRS) in multispeckled laser beams has been identified in the trapping regime over a wide range of k{lambda}{sub D} values (here k is the wave number of the electron plasma waves and {lambda}{sub D} is the Debye length) in homogeneous and inhomogeneous plasmas. Hot electrons from intense speckles, both forward and sideloss hot electrons produced during SRS daughter electron plasma wave bowing and filamentation, seed and enhance the growth of SRS in neighboring speckles by reducing Landau damping. Trappingenhanced speckle interaction through transport of hot electrons, backscatter, and sidescatter SRSmore »