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Scattering of electromagnetic waves by an non-uniform cylindrical plasma; Diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene

Abstract

The problem of the scattering of plane electromagnetic waves from a non-uniform, cylindrically symmetrical plasma is solved analytically, by a self-consistent field method, for a wave with the electric field parallel to the cylinder axis. Numerical results for the diffracted field are plotted for interesting ranges of the parameters involved: diameter, density on the axis, radial profile of the density, and collision frequencies. The case where the incident field is cylindric (waves surfaces parallel to the cylinder axis) is examined - this permits to connect theoretical calculations and experimental diffraction patterns, and also to explain the diffraction effects observed in a classical microwave interferometry experiment. These results, and the possibility of measuring exactly the diffracted field (showed by experiments with dielectric and metallic rods) lead to a new plasma diagnostic method, based on the diffraction, which has no theoretical limitations and it usable when the classical free-space wave methods are not (plasma diameter lower than 10 wave lengths). The feasibility of this method is tested with a plasma at atmospheric pressure and a 2 mm incident wavelength. The plasma is obtained by the laminar flow of a plasma torch, with a working gas (He or Ar) seeded by potassium (density  More>>
Authors:
Faugeras, P E [1] 
  1. Commissariat a l'Energie Atomique, Fontenay-aux-Roses (France). Centre d'Etudes Nucleaires. Groupe de recherches sur la fusion controlee
Publication Date:
Jul 01, 1967
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-3133
Resource Relation:
Other Information: 43 refs
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CYLINDRICAL CONFIGURATION; DIFFRACTION; DIFFUSION; ELECTROMAGNETIC RADIATION; FEASIBILITY STUDIES; PARAMETRIC ANALYSIS; PLASMA; VALIDATION
OSTI ID:
20650663
Research Organizations:
Commissariat a l'Energie Atomique, Fontenay-aux-Roses (France). Centre d'Etudes Nucleaires; Faculte des Sciences de l'Universite de Paris, Centre d'Orsay, 91 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR05R3133090276
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
54 pages
Announcement Date:
Nov 23, 2005

Citation Formats

Faugeras, P E. Scattering of electromagnetic waves by an non-uniform cylindrical plasma; Diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene. France: N. p., 1967. Web.
Faugeras, P E. Scattering of electromagnetic waves by an non-uniform cylindrical plasma; Diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene. France.
Faugeras, P E. 1967. "Scattering of electromagnetic waves by an non-uniform cylindrical plasma; Diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene." France.
@misc{etde_20650663,
title = {Scattering of electromagnetic waves by an non-uniform cylindrical plasma; Diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene}
author = {Faugeras, P E}
abstractNote = {The problem of the scattering of plane electromagnetic waves from a non-uniform, cylindrically symmetrical plasma is solved analytically, by a self-consistent field method, for a wave with the electric field parallel to the cylinder axis. Numerical results for the diffracted field are plotted for interesting ranges of the parameters involved: diameter, density on the axis, radial profile of the density, and collision frequencies. The case where the incident field is cylindric (waves surfaces parallel to the cylinder axis) is examined - this permits to connect theoretical calculations and experimental diffraction patterns, and also to explain the diffraction effects observed in a classical microwave interferometry experiment. These results, and the possibility of measuring exactly the diffracted field (showed by experiments with dielectric and metallic rods) lead to a new plasma diagnostic method, based on the diffraction, which has no theoretical limitations and it usable when the classical free-space wave methods are not (plasma diameter lower than 10 wave lengths). The feasibility of this method is tested with a plasma at atmospheric pressure and a 2 mm incident wavelength. The plasma is obtained by the laminar flow of a plasma torch, with a working gas (He or Ar) seeded by potassium (density continuously variable between 10{sup 11} and 10{sup 15} e/cm{sup 3}. Some diffraction patterns by this plasma and for various incident waves, are also given and explained with theoretical calculations. (author) [French] On etudie la diffusion coherente d'une onde electromagnetique par un cylindre de plasma inhomogene par une methode de champ self-consistant, et pour une onde de vecteur electrique parallele a l'axe du cylindre. On a calcule le champ diffracte en faisant varier le diametre du cylindre, la densite sur l'axe, le profil de densite et les frequences de collisions, et on donne ici les principaux resultats. On examine ensuite le cas d'une onde incidente cylindrique (surfaces d'onde paralleles a l'axe du cylindre). Ceci permet de relier les resultats theoriques aux diagrammes de diffraction experimentaux, et aussi d'expliquer les phenomenes, de diffraction qui faussent l'interpretation des mesures par interferometrie hyperfrequence. Ces resultats, joints a la possibilite de mesurer exactement le champ diffracte (ce que nous avons montre avec des cylindres dielectriques et metalliques) conduisent a une nouvelle methode de diagnostic d'un plasma, basee sur la diffraction. Sans limitations theoriques, cette methode est applicable la ou les methodes hyperfrequences classiques ne le sont pas (diametre du plasma inferieur a 10 longueurs d'onde).Cette methode a ete experimentee sur plasma a la pression atmospherique, avec une onde incidente de 2 mm. Le plasma est engendre par le jet laminaire d'une torche a plasma, fonctionnant avec de l'helium ou de l'argon ensemence au potassium (la densite peut ainsi varier de facon continue entre 10{sup 11} et 10{sup 15} e/cm{sup 3}). On donne egalement quelques diagrammes de diffraction par ce plasma, releves pour differents champs incidents, et interpretes par les resultats theoriques precedents. (auteur)}
place = {France}
year = {1967}
month = {Jul}
}