|ship_icc2006.pdf||2006-03-22 03:17:13||Andrej Lizunov|
CONFINEMENT OF STRONGLY ANISOTROPIC HOT-ION PLASMA IN A COMPACT MIRROR
Author: Andrej A. Lizunov
Submitted: 2006-01-05 17:07:33
Co-authors: A.V. Anikeev, P.A. Bagryansky, A.A. Ivanov, S.V. Murakhtin, V.V. Prikhodko, A.L. Solomakhin, and K. Noack
Budker Institute of Nuclear Physics
Lavrentiev prospect 11
Novosibirsk, - 630090
Development of the powerful neutron source for first wall material treatment is a high-priority task of the fusion technology studies beyond ITER. One of approaches is a project of 14-MeV volumetric neutron source based on the gas dynamic trap (GDT) version with multi-component plasma . To provide both the physics database and technologies necessary for this project, in 1986 experiments on the model of a gas dynamic trap  was started in BINP. The primary target of the GDT experiment is the study of confinement of high-beta anisotropic plasma with thermonuclear ions . The most recent GDT program study was aimed at formation of a dense plasma with fusion ions having strongly anisotropic distributions, in a relatively small volume. This so called Synthesised Hot Ion Plasmoid (SHIP) experiment pursues two key goals: (1) to simulate directly the conditions very close to that expected in the testing zones of a GDT-based neutron source and (2) to achieve confinement improvement of two-component plasma in the gas dynamic trap.
Anisotropic ions are produced by the perpendicular injection of two focused 18 keV neutral beams in the small mirror section attached to the GDT central cell. Magnetic field amounts 2.5 T on the section axis with the mirror ration of ≈2. The presented first-step experiments were performed with moderate injected beam current of 50 atom Amperes in a 1 ms pulse. We observed build-up of density of anisotropic ions up to approximately 10^19 m^-3 with the localized spatial profile and the mean energy of 10 keV. Measurements of the plasma linear density enabled us to estimate the average fast ion density three times exceeding the background plasma density. At the same time, recorded decrease of the axial plasma flux from the central cell was qualified as a potential barrier development, which causes an additional ion flux suppression. Obtained experimental results correlate well with numerical simulations made using the ITCS Monte-Carlo code, giving a reasonable optimism to scale to the further projected parameters of SHIP neutral beam injection: energy of 25 keV, beam current of 100 atom Amperes and pulse duration of 1.5-2 ms.
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