Neutral particle balance in GDT with fast titanium coating of the first wall

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:178202

Bagryansky, P A; Bender, E D; Ivanov, A A; Krahl, S; Noack, K; Karpushov, A N; Murakhtin, S V; Shikhovtsev, I V ^[1]

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1. Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation)

The GDT is an axisymmetric open trap with a high mirror ratio for confinement of a collisional plasma. The experimental program of the GDT was focused on the generation of plasma physics database necessary for a GDT-based neutron source. A distinct feature of both GDT and the GDT-based neutron source is that the Larmor radius of the fast sloshing ions is comparable to plasma radius. In this case, the sloshing ions can not be well shielded by the plasma halo from penetration of the neutral gas from periphery that results in high charge exchange losses. The plasma parameters are then very sensitive to gas pressure near the plasma boundary. To reduce the gas pressure to desured value during the beam heating, the authors have used arc-type evaporators developed at the Budker INP for fast titanium coating of the GDT first wall. If needed, the coating can be done a few seconds before each shot. They investigated the neutral particle balance in presence of NB-heating. The inverted magnetron gauges were used to study the temporal dependence of gas pressure inside the central cell. Pyroelectric bolometers were employed to measure the flux of charge exchange neutrals. Neutral particle balance has also been studied numerically by using a gas-transport code. The results of the investigations are the following: (1) sloshing ion lifetime was increased about 10 times compared to that without the coating of the first wall; and (2) wall recycling coefficient of the Ti-coated wall does not exceed 1 for 8 keV mean energy of the neutral hydrogen atoms striking the wall.

• OSTI ID: 178202
• Report Number(s): CONF-950612--; ISBN 0-7803-2669-5
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM INJECTION HEATING
ENERGY BALANCE
ENERGY LOSSES
FIRST WALL
INFORMATION NEEDS
MAGNETIC CONFINEMENT
MAGNETIC MIRRORS
NEUTRON SOURCES
PRESSURE DEPENDENCE
PROTECTIVE COATINGS