Published March 1969 | Version v1
Book

Investigation of the Mechanism of Beam Heating of a Plasma in a Magnetic Mirror Trap

  • 1. Institut Atomnoj Energii IM. I.V. Kurchatova, Moskva, SSSR (Russian Federation)

Description

The authors investigate the heating of electrons by a powerful electron beam passing through a cold plasma. The experimental facility consists of a magnetic mirror machine with a large mirror ratio. The maximum magnetic field is 2 kOe at the middle of the trap and 10.5 kOe in the mirrors. The pulsed electron beam, with a current of up to 20 A and an accelerating voltage of up to 35 kV, is injected along the magnetic field into the trap, which contains a previously prepared cold plasma. The trap is filled with this cold hydrogen plasma by means of a titanium injector. The initial plasma concentration is (1-2) x 1012 cm-3 and the temperature 5-10 eV. During the passage of the electron beam the total plasma concentration remains virtually unchanged, but the electron distribution function changes substantially. The plasma breaks down into two components that differ considerably in density and temperature. The hot electron concentration reaches a value of 1010 cm-3. The mean energy of these electrons (as high as 200 keV) significantly exceeds the energy of the beam particles. The electron energy depends on the duration of the electron pulse, the strength of the magnetic field, and the transverse dimensions of the plasma. The containment time for the hot plasma is limited by collisions with the neutral gas. The plasma is observed to emit X-rays over a period of 5-10 s. The hot plasma expands rapidly across the magnetic field and achieves dimensions exceeding the transverse dimensions of the beam by a factor of more than 20. The expansion rate depends on the magnetic field and the beam parameters. Expansion of the plasma is accompanied by an increase in electron energy, while the mean energy density of the hot plasma remains constant even when the plasma volume changes by a factor of more than 10. In the small region occupied by the beam, the energy density of the hot plasma exceeds the overall mean density by a factor of about two. The authors propose a beam heating model based on the assumption that the source of accelerated particles is an electron beam. The experimental results are in satisfactory agreement with this model. (author)

Abstract (Russian)

Issleduetsja nagrev jelektronov pri prohozhdenii moshhnogo jelektronnogo puchka cherez holodnuju plazmu. Jeksperimental'naja ustanovka predstavljaet soboj probkotron s bol'shim probochnym otnosheniem. Maksimal'noe magnitnoe pole v centre lovushki - 2 kje, v probkah — 10,5 kje . Impul'snyj jelektronnyj puchok s tokom do 20 a i uskorjajushhim naprjazheniem do 35 kv inzhektiruetsja vdol' magnitnogo polja v lovushku s zaranee podgotovlennoj holodnoj plazmoj. Dlja zapolnenija lovushki holodnoj vodorodnoj plazmoj primenjaetsja titanovyj inzhektor. Nachal'naja koncentracija plazmy (1 *2) 1012 CM-3 I temperatura - 5 -f 10 je v. Vo vremja prohozhdenija jelektronnogo puchka polnaja koncentracija plazmy prakticheski ostaetsja neizmennoj, no funkcija raspredelenija jelektronov sushhestvenno izmenjaetsja. Plazma stanovitsja dvuhkomponentnoj. Komponenty sil'no razlichajutsja po plotnosti i temperature. Koncentracija gorjachih jelektronov dostigaet 1010 sm-3 . Srednjaja jenergija jetih jelektronov znachitel'no prevyshaet jenergiju chastic puchka, dostigaja 200 kjev. Jenergija jelektronov zavisit ot dlitel'nosti jelektronnogo impul'sa, naprjazhennosti magnitnogo polja, poperechnyh razmerov plazmy. Vremja uderzhanija gorjachej plazmy ogranichivaetsja stolknovenijami s nejtral'nym gazom. Rentgenovskoe izluchenie iz plazmy nabljudaetsja v techenie 5-10 sek. Gorjachaja plazma s bol'shoj skorost'ju rasshirjaetsja poperek magnitnogo polja do razmerov, prevyshajushhih poperechnye razmery puchka bolee chem v 20 r a z. Skorost' rasshirenija zavisit ot velichiny magnitnogo polja i parametrov puchka. Rasshirenie plazmy soprovozhdaetsja uvelicheniem jenergii jelektronov,a srednjaja plotnost' jenergii gorjachej plazmy ostaetsja postojannoj pri izmenenii ee obema bol'she chem v 10 raz. V nebol'shoj oblasti, zanimaemoj puchkom, plotnost' jenergii gorjachej plazmy prevyshaet srednjuju plotnost' v bol'shom obeme primerno v 2 raza. Predlagaetsja model' puchkovogo nagreva, osnovannaja na predpolozhenii o tom, chto istochnikom uskorjaemyh chastic javljaetsja jelektronnyj puchok. Jeksperimental'nye rezul'taty udovletvoritel'no soglasujutsja s jetoj model'ju. (author)

Additional details

Additional titles

Original title (Russian)
Issledovanie mekhanizma puchkovogo nagreva plazmy v probkotrone

Publishing Information

Publisher
IAEA
Imprint Place
Vienna (International Atomic Energy Agency (IAEA))
Imprint Title
Plasma Physics and Controlled Nuclear Fusion Research. Proceedings of the Third International Conference on Plasma Physics and Controlled Nuclear Fusion Research. Vol. II
Imprint Pagination
852 p.
Journal Series
Proceedings Series
Journal Page Range
p. 709-721
ISSN
0074-1884

Conference

Title
3. international conference on plasma physics and controlled nuclear fusion research
Dates
1-7 Aug 1968
Place
Novosibirsk, USSR (Russian Federation)

INIS

Country of Publication
International Atomic Energy Agency (IAEA)
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
44064146
Subject category
S70: PLASMA PHYSICS AND FUSION TECHNOLOGY;
Resource subtype / Literary indicator
Conference
Quality check status
Yes
Descriptors DEI
COLD PLASMA; DISTRIBUTION FUNCTIONS; ELECTRON BEAMS; ELECTRONS; ENERGY DENSITY; EV RANGE; HEATING; HOT PLASMA; HYDROGEN; KEV RANGE; MAGNETIC FIELDS; MAGNETIC MIRRORS; MIRROR RATIO; PULSES; TITANIUM; TRAPS; X RADIATION;
Descriptors DEC
BEAMS; DIMENSIONLESS NUMBERS; ELECTROMAGNETIC RADIATION; ELEMENTARY PARTICLES; ELEMENTS; ENERGY RANGE; FERMIONS; FUNCTIONS; IONIZING RADIATIONS; LEPTON BEAMS; LEPTONS; METALS; NONMETALS; OPEN PLASMA DEVICES; PARTICLE BEAMS; PLASMA; RADIATIONS; THERMONUCLEAR DEVICES; TRANSITION ELEMENTS;

Optional Information

Lead record
61a4m-c8n42
Notes
14 refs., 9 figs. Imprint:In two volumes
Secondary number(s)
IAEA-CN--24/L-3