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Plasma-Column Equilibrium in Tokamak-5; L'Equilibre d'une Colonne de Plasma dans l'Installation Tokamak-5; Issledovanie ravnovesiya plazmennogo shnura na ustanovke Tokamak-5; El Equilibrio de una Columna de Plasma en la Instalacion 'Tokamak-5'

Abstract

This paper, which is a continuation of work done by Grigorovich and Mukhovatov, is devoted to an investigation of the conditions of equilibrium of the plasma column in Tokamak-5. This equipment has the following parameters: large radius of the copper casing R = 62. 5 cm, small radius b = 25 cm, small radius of the liner = 20 cm, radius of the opening in the diaphragm = 15 cm (the centre of the opening in the diaphragm and the centre of the cross-section of the casing coincide), intensity of the longitudinal magnetic field B{sub 0} = 6 to 12 kOe and current in the plasma J = 15 to 20 kA, The tests were carried out at an initial hydrogen pressure of (1.8 to 5.0) x 10{sup -4} Torr. Between the casing and the liner were placed conductors, used to set up within the chamber a transverse magnetic field B{sub z} varying synchronously with the discharge current. Grigorovich and Mukhovatov had demonstrated qualitative agreement of experimental results with the hypothesis that the column is maintained in equilibrium by the copper casing, and had shown that the average electrical conductivity of the plasma over the cross-section of the column reaches  More>>
Authors:
Muhovatov, V. S. [1] 
  1. Institut Atomnoj Ehnergii, Im. I.V. Kurchatova, Moskva, SSSR (Russian Federation)
Publication Date:
Apr 15, 1966
Product Type:
Conference
Report Number:
IAEA-CN-21/147
Resource Relation:
Conference: Conference on Plasma Physics and Controlled Nuclear Fusion Research, Culham (United Kingdom), 6-10 Sep 1965; Other Information: 12 refs., 8 figs.; Related Information: In: Plasma Physics and Controlled Nuclear Fusion Research. Vol. II. Proceedings of a Conference on Plasma Physics and Controlled Physics Research Nuclear Fusion Research| 1017 p.
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COPPER; COVERINGS; DIAPHRAGM; ELECTRIC CONDUCTIVITY; ELECTRIC CURRENTS; ELECTRIC POTENTIAL; ELECTRON TEMPERATURE; EXPERIMENTAL DATA; HYDROGEN; MAGNETIC FIELDS; PLASMA; TOKAMAK DEVICES
OSTI ID:
22178061
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
Russian
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M2281002505
Submitting Site:
INIS
Size:
page(s) 577-593
Announcement Date:
Jan 09, 2014

Citation Formats

Muhovatov, V. S. Plasma-Column Equilibrium in Tokamak-5; L'Equilibre d'une Colonne de Plasma dans l'Installation Tokamak-5; Issledovanie ravnovesiya plazmennogo shnura na ustanovke Tokamak-5; El Equilibrio de una Columna de Plasma en la Instalacion 'Tokamak-5'. IAEA: N. p., 1966. Web.
Muhovatov, V. S. Plasma-Column Equilibrium in Tokamak-5; L'Equilibre d'une Colonne de Plasma dans l'Installation Tokamak-5; Issledovanie ravnovesiya plazmennogo shnura na ustanovke Tokamak-5; El Equilibrio de una Columna de Plasma en la Instalacion 'Tokamak-5'. IAEA.
Muhovatov, V. S. 1966. "Plasma-Column Equilibrium in Tokamak-5; L'Equilibre d'une Colonne de Plasma dans l'Installation Tokamak-5; Issledovanie ravnovesiya plazmennogo shnura na ustanovke Tokamak-5; El Equilibrio de una Columna de Plasma en la Instalacion 'Tokamak-5'." IAEA.
@misc{etde_22178061,
title = {Plasma-Column Equilibrium in Tokamak-5; L'Equilibre d'une Colonne de Plasma dans l'Installation Tokamak-5; Issledovanie ravnovesiya plazmennogo shnura na ustanovke Tokamak-5; El Equilibrio de una Columna de Plasma en la Instalacion 'Tokamak-5'}
author = {Muhovatov, V. S.}
abstractNote = {This paper, which is a continuation of work done by Grigorovich and Mukhovatov, is devoted to an investigation of the conditions of equilibrium of the plasma column in Tokamak-5. This equipment has the following parameters: large radius of the copper casing R = 62. 5 cm, small radius b = 25 cm, small radius of the liner = 20 cm, radius of the opening in the diaphragm = 15 cm (the centre of the opening in the diaphragm and the centre of the cross-section of the casing coincide), intensity of the longitudinal magnetic field B{sub 0} = 6 to 12 kOe and current in the plasma J = 15 to 20 kA, The tests were carried out at an initial hydrogen pressure of (1.8 to 5.0) x 10{sup -4} Torr. Between the casing and the liner were placed conductors, used to set up within the chamber a transverse magnetic field B{sub z} varying synchronously with the discharge current. Grigorovich and Mukhovatov had demonstrated qualitative agreement of experimental results with the hypothesis that the column is maintained in equilibrium by the copper casing, and had shown that the average electrical conductivity of the plasma over the cross-section of the column reaches its maximum if by means of the transverse field B{sub z} the column is arranged concentrically with the opening in the diaphragm. The present paper shows that in most discharge regimes there is good quantitative agreement between the experimental data and the theory of column equilibrium within the conducting casing. However, in a number of discharge regimes (with low initial gas pressures and high values of displacement {Delta}{sub B} = b{sup 2}B{sub z}c/2J directed towards the inner wall of the torus) there is a certain discrepancy between theory and experiment. An attempt was made to assess to what extent the process of cutting off drift current by the conducting diaphragm contributes to maintaining equilibrium of the column in Tokamak. For this purpose the diaphragm was cut into six segments isolated from each other. During a discharge at B{sub z} = 0, a polarized voltage appeared between the upper and lower segments; this was almost one order of magnitude higher than the electron temperature calculated from the average electrical conductivity of the plasma. At the optimum value of B{sub z} the potential difference was close to zero, and changed its sign with further increase in B{sub z}. A similar dependence on B{sub z} was observed for the currents flowing between the segments when they were connected by low resistance. Connecting all the segments together did not lead to any noticeable change in the displacement of the column or in the other characteristics of the discharge. The current measured between the segments remained insufficient to explain the discrepancy mentioned above, the more so since the latter also occurred when the segments were isolated. The possible causes of this discrepancy are discussed, together with the reasons for the high potential difference between the segments. (author) [French] L'etude exposee dans le memoire fait suite aux travaux de Grigorovitch et Moukhovatov sur les conditions d'equilibre d'une colonne de plasma dans l'installation Tokamak-5. Les caracteristiques de cette installation sont les suivantes; enveloppe en cuivre, grand rayon R = 62,5 cm, petit rayon b= 25 cm; petit rayon du revetement interieur - 20 cm; rayon de l'ouverture du diaphragme - 15 cm (le centre de cette ouverture et celui de la coupe de l'enveloppe coiencident); champ magnetique longitudinal B = 6 a 12 kOe, intensite du courant dans le plasma J = 15 a 20 kA. Au cours des experiences, la pression initiale de l'hydrogene etait de 1,8 a 5 * 10{sup -4} Torr. Entre l'enveloppe et le revetement interieur, on avait dispose des conducteurs qui permettaient de creer a l'interieur de la chambre un champ magnetique transversal B{sub z}, dont les variations etaient synchronisees avec celles. du courant de decharge. Grigorovitch et Mouhkovatov ont montre que les resultats des experiences concordaient qualitativement avec la theorie selon laquelle la colonne de plasma est maintenue en equilibre par l'enveloppe de cuivre. Ils ont egalement etabli que la moyenne de la conductivite electrique du plasma, sur la section de la colonne, atteignait sa valeur maximale lorsque la colonne est disposee de facon concentrique par rapport a l'ouverture du diaphragme, grace au champ transversal B{sub z}. L'auteur montre que pour la plupart des regimes de decharge il existe une bonne concordance quantitative entre les donnees experimentales et la theorie concernant l'equilibre de la colonne a l'interieur de l'enveloppe conductrice. Cependant, pour plusieurs regimes de decharge (faible pression initiale du gaz et fort deplacement {Delta}{sub B} = b{sup 2}B{sub z}c/2J vers la paroi interieure du tore), il a observe une certaine divergence entre la theorie et l'experience. Il a essaye d'evaluer dans quelle mesure le mecanisme de fermeture du circuit des courants de derive au moyen du diaphragme conducteur pouvait contribuer a maintenir l'equilibre de la colonne dans l'installation Tokamak. A cet effet, le diaphragme a ete divise en six segments isoles l'un de l'autre. Au cours de decharges a B{sub z} = 0, on a observe entre les segments superieurs et inferieurs une tension polarisee, depassant de pres d'un ordre de grandeur la temperature des electrons, calculee d'apres la conductivite electrique moyenne du plasma. Pour la valeur optimum de B{sub z}, la tension etait proche de zero; si l'on continuait d'augmenter B{sub z}, elle changeait de signe. L'auteur a egalement observe une dependance analogue de B{sub z} pour les courants passant entre les segments lorsqu'ils etaient connectes par une faible resistance. L'interconnexion de tous les segments n'a pas sensiblement modifie la grandeur du deplacement de la colonne ni les autres caracteristiques de la decharge. Le courant mesure entre les segments est insuffisant pour expliquer la divergence susmentionnee, d'autant plus qu'on l'observe egalement lorsque les segments sont isoles. L'auteur examine les causes possibles de cette divergence et celles qui provoquent l'apparition d'une forte tension entre les segments. (author) [Spanish] Esta memoria se refiere al estudio de las condiciones de equilibrio de una columna de plasma en la instalacion Tokamak-5. Los parametros de la instalacion son los siguientes: radio mayor de la camara de cobre R = 62,5 cm, radio menor b = 25 cm, radio menor del revestimiento = 20 cm, radio de la abertura del diafragma = 15 cm (el centro del diafragma coincide con el centro de la seccion transversal de la vasija); intensidad del campo magnetico axial B{sub 0} = 6 a 12 kOe, intensidad de la corriente en el plasma I = 15 a 20 kA. Se han efectuado los experimentos con una presion inicial del hidrogeno (1,8 a 5,0) * 10{sup -4} Torr. Entre la camara y el revestimiento se colocaron unos conductores mediante los cuales so originaba, en el volumen de la camara, un campo magnetico transversal B{sub z}, que variaba sincronicamente con la corriente de descarga. En una memoria anterior se demostro la concordancia cualitativa de los resultados experimentales con la hipotesis de que la columna de plasma es mantenida en equilibrio por la camara de cobre. Se indicaba tambien que la conductividad media del plasma respecto de la seccion de la columna alcanza su valor maximo si, por medio de un campo transversal B{sub z}, se situa la columna concentricamente respecto de la abertura del diafragma. En la presente memoria se muestra que, en la mayoria de los regimenes de descarga se tiene buena concordancia cualitativa entre los datos experimentales y la teorfa del equilibrio de la columna del plasma dentro de una camara conductora. Sin embargo, en una serie de regimenes de descarga (con bajas presiones iniciales del gas y valores elevados del desplazamiente {Delta}{sub B} = b{sup 2}B{sub z}c/2J hacia la pared interior del toro) se observo cierta discrepancia entre los datos teoricos y experimentales. Se preparo un experimento para estimar la importancia de la contribucion al mantenimiento del equilibrio de la columna de plasma en el Tokamak, que es debido al mecanismo de cortocircuito de las corrientes de deriva por el diafragma conductor. A este fin, se dividio el diafragma en seis segmentos, aislados unos de otros. En el proceso de la descarga, con B{sub z} = 0, entre los segmentos superiores y los inferiores se observo una diferencia de potencial unipolar, casi de un orden de magnitud mayor que la temperatura electronica, calculada a partir de la conductividad electrica media del plasma. Para el valor optimo de B{sub z}, la diferencia de potencial era casi nula y, con un aumento posterior de B{sub z}, cambiaba de signo. Se observo una dependencia analoga, respecto de B{sub z}, en el caso de las corrientes que circulaban entre los segmentos al cerrar el circuito mediante resistencias de algunos ohmios. El contacto electrico de todos los segmentos entre sf, no producia una variacion apreciable de la magnitud del desplazamiento de la columna de plasma, ni de otras caracteristicas de la descarga. El valor, que se ha medido, de la corriente entre segmentos, no es suficiente para explicar la disparidad antes mencionada, tanto mas cuanto que se observa tambien estando los segmentos aislados. Se examinan las causas posibles de dicha discrepancia y los motivos de la aparicion de la gran diferencia de potencial entre los segmentos. (author) [Russian] Rabota posvjashhena issledovaniju uslovij ravnovesija plazmennogo shnura v ustanovke Toka- mak-5. Jeta ustanovka imeet sledujushhie parametry: bol'shoj radius mednogo kozhuha V = 62,5 sm, ego malyj radius b = 25 sm, malyj radius lajnera -20 sm, radius otverstija diafragmy - 15 sm (centr otverstija diafragmy i centr poperechnogo sechenija kozhuha sovpadajut), naprjazhennost' prodol'nogo magnitnogo polja B{sub 0} =6 Division-Sign 12 kje, velichina toka v plazme J = 15 Division-Sign 20 ka. Opyty provodilis' pri nachal'nom davlenii vodoroda (1,8 Division-Sign 5) * 10{sup -4} torr. Mezhdu kozhuhom i lajnerom byli prolozheny provodniki, s pomoshh'ju kotoryh v ob{sup e}me kamery sozdavalos' poperechnoe magnitnoe pole B{sub z}, izmenjajushheesja sinhronno s razrjadnym tokom. Bylo prodemonstrirovano kachestvennoe soglasie rezul'tatov jeksperimentov s predstavlenijami o tom, chto shnur uderzhivaetsja v ravnovesii mednym kozhuhom. Bylo takzhe pokazano, chto srednjaja po secheniju shnura jelektroprovodnost' plazmy dostigaet maksimuma, esli s pomoshh'ju poperechnogo polja V 2 shnur raspolagaetsja koncentrichno otnositel'no otverstija diafragmy. V nastojashhej rabote pokazano, chto v bol'shinstve rezhimov razrjada imeetsja horoshee kolichestvennoe soglasie mezhdu jeksperimental'nymi dannymi i teoriej ravnovesija shnura vnutri provodjashhego kozhuha. Odnako v rjade rezhimov razrjada (pri nizkih nachal'nyh davlenijah gaza i bol'shih velichinah smeshhenija {Delta}{sub B} = b{sup 2}B{sub z}c/2J,napravlennogo k vnutrennej stenke tora) nabljudalos' nekotoroe rashozhdenie mezhdu teoriej i jeksperimentom. Byla predprinjata popytka ocenit', naskol'ko sushhestvennyj vklad v podderzhanie ravnovesija shnura v Tokamake mozhet vnosit' mehanizm zamykanija drejfovyh tokov provodjashhej diafragmoj. Dlja jetoj celi diafragma byla razdelena na shest' izolirovannyh drug ot druga segmentov. V processe razrjada pri B{sub z} =0 mezhdu verhnim i nizhnim segmentami nabljudalas' odnopoljarnaja raznost' potencialov, pochti na porjadok velichiny prevyshajushhaja jelektronnuju temperaturu, vychislennuju po srednej jelektroprovodnosti plazmy. Pri optimal'nom znachenii B{sub z} raznost' potencialov byla blizka k nulju i pri dal'nejshem uvelichenii B{sub z} menjala znak. Analogichnaja zavisimost' ot B{sub z} nabljudalas' i dlja tokov, protekajushhih mezhdu segmentami pri zamykanii ih cherez nizkoomnoe soprotivlenie. Zamykanie vseh segmentov drug s drugom ne privodilo k zametnomu izmeneniju velichiny smeshhenija shnura i drugih harakteristik razrjada. Izmerjaemaja velichina toka mezhdu segmentami nedostatochna, chtoby ob{sup j}asnit' ukazannoe vyshe rashozhdenie, tem bolee, chto ono nabljudaetsja i pri izolirovannyh segmentah. Obsuzhdajutsja vozmozhnye prichiny takogo rashozhdenija i prichiny, obuslovlivajushhie vozniknovenie mezhdu segmentami bol'shoj raznosti potencialov. (author)}
place = {IAEA}
year = {1966}
month = {Apr}
}