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Development of a method for studying non-linear phenomena in plasma; Mise au point d'une methode d'etude des phenomenes non lineaires dans un plasma

Abstract

The study of non-linear phenomena resulting from the interaction of powerful electro-magnetic waves with an electron gas is the basis of the p best methods for measuring the frequency of electronic collisions in the ionosphere. In laboratory plasma the appearance of these phenomena is connected with a powerful critical field. Although we have used a relatively low-power electromagnetic source, we have been able to develop a simple hyper-frequency method making it possible to study these phenomena to measure them and to put forward an elementary interpretation. An electromagnetic wave provided by a 1 watt klystron interacts with a HF discharge (25 MHz) in the volume of a TE{sub 111} cavity. The tube containing the discharge and the axis of the cylindrical cavity are co-linear with a magnetic field which can attain a value such that the wave frequency is equal to the gyromagnetic frequency of the electrons. The resonance curve for the cavity, which depends on the electronic density and the frequency of collisions, becomes increasingly dissymmetric as the absorbed power increases and as the gyromagnetic frequency of the electrons approaches that of the incident wave. By studying the resonance, it is possible to calculate the proportionality coefficients relating the  More>>
Authors:
Gonfalone, A [1] 
  1. Commissariat a l'Energie Atomique, Fontenay-aux-Roses (France). Centre d'Etudes Nucleaires
Publication Date:
Mar 01, 1965
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-2758
Resource Relation:
Other Information: TH: These fusion controlee; 13 refs
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CRITICAL FIELD; ELECTROMAGNETIC RADIATION; ELECTRON COLLISIONS; ELECTRON DENSITY; ELECTRON GAS; ELECTRON TEMPERATURE; IONOSPHERE; KLYSTRONS; PLASMA
OSTI ID:
20680240
Research Organizations:
CEA Fontenay-aux-Roses, 92 (France); Association Euratom-CEA, Centre d'Etudes Nucleaires de Fontenay-aux-Roses, 92 (France). Groupe de Recherches sur la Fusion Controlee
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR05R2758115130
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
86 pages
Announcement Date:
Jan 07, 2006

Citation Formats

Gonfalone, A. Development of a method for studying non-linear phenomena in plasma; Mise au point d'une methode d'etude des phenomenes non lineaires dans un plasma. France: N. p., 1965. Web.
Gonfalone, A. Development of a method for studying non-linear phenomena in plasma; Mise au point d'une methode d'etude des phenomenes non lineaires dans un plasma. France.
Gonfalone, A. 1965. "Development of a method for studying non-linear phenomena in plasma; Mise au point d'une methode d'etude des phenomenes non lineaires dans un plasma." France.
@misc{etde_20680240,
title = {Development of a method for studying non-linear phenomena in plasma; Mise au point d'une methode d'etude des phenomenes non lineaires dans un plasma}
author = {Gonfalone, A}
abstractNote = {The study of non-linear phenomena resulting from the interaction of powerful electro-magnetic waves with an electron gas is the basis of the p best methods for measuring the frequency of electronic collisions in the ionosphere. In laboratory plasma the appearance of these phenomena is connected with a powerful critical field. Although we have used a relatively low-power electromagnetic source, we have been able to develop a simple hyper-frequency method making it possible to study these phenomena to measure them and to put forward an elementary interpretation. An electromagnetic wave provided by a 1 watt klystron interacts with a HF discharge (25 MHz) in the volume of a TE{sub 111} cavity. The tube containing the discharge and the axis of the cylindrical cavity are co-linear with a magnetic field which can attain a value such that the wave frequency is equal to the gyromagnetic frequency of the electrons. The resonance curve for the cavity, which depends on the electronic density and the frequency of collisions, becomes increasingly dissymmetric as the absorbed power increases and as the gyromagnetic frequency of the electrons approaches that of the incident wave. By studying the resonance, it is possible to calculate the proportionality coefficients relating the density and collision frequency variations with the absorbed power. The experiments were carried out by causing the following to vary separately: the incident UHF power, the initial electronic density, the pressure of the neutral ambient gas, and the axial magnetic field. The variation in the electronic density as a function of the magnetic field for a high UHF power shows a resonance of dissymmetrical form, sometimes with a sharp peak in the neighbourhood of {omega}{sub H}. The possibility of applying these properties to the construction of practical devices, is under consideration. (author) [French] L'etude des phenomenes non lineaires dus a l'interaction d'ondes electro-magnetiques puissantes avec un gaz d'electrons est a la base des meilleures methodes de mesure des frequences de collisions electroniques dans l'ionosphere. Dans les plasmas de laboratoire l'apparition de ces phenomenes est liee a un champ critique de valeur elevee. Tout en n'utilisant qu'une source electromagnetique de puissance relativement faible, nous avons mis au point une methode hyperfrequence simple qui permet de mettre ces phenomenes en evidence, de les mesurer et d'en donner une interpretation elementaire. Une onde electromagnetique, fournie par un klystron de 1 W de puissance, interagit avec une decharge HF (25 MHz) dans le volume d'une cavite TE{sub 111}. Le tube contenant la decharge et l'axe de la cavite cylindrique sont colineaires a un champ magnetique pouvant atteindre une valeur telle que la frequence de l'onde soit egale a la frequence gyromagnetique des electrons. La courbe de resonance de la cavite, qui depend de la densite electronique et de la frequence des collisions, devient d'autant plus dissymetrique que la puissance absorbee est grande et que la frequence gyromagnetique des electrons est voisine de la frequence de l'onde incidente. L'etude de la resonance permet de calculer les coefficients de proportionnalite qui relient les variations de la densite et de la frequence de collisions a la puissance absorbee. Les experiences ont ete faites en faisant varier separement: la puissance UHF incidente, la densite electronique initiale, la pression du gaz neutre ambiant, ainsi que le champ magnetique axial. La variation de la densite electronique en fonction du champ magnetique pour une puissance UHF forte, montre une resonance de forme dissymetrique avec quelquefois un pic aigu, au voisinage de {omega}{sub H}. L'application eventuelle des proprietes mises en evidence a la realisation de dispositifs pratiques est envisagee. (auteur)}
place = {France}
year = {1965}
month = {Mar}
}