Beam deflection by plasma grid filter current in the negative-ion source for JT-60U neutral beam injection system

Journal Article · Wed Mar 15 00:00:00 EST 2006 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.2170088· OSTI ID:20779014

Umeda, N; Ikeda, Y; Hanada, M; Inoue, T; Kawai, M; Kazawa, M; Komata, M; Mogaki, K; Ohga, T ^[1]

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1. Naka Fusion Institute, Japan Atomic Energy Agency, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan)

In the JT-60U negative-ion-based neutral beam injection system, the effect of negative ion and electron deflection by the plasma grid (PG) magnetic filter was studied. After a long-pulse operation of up to 19 s, a local melting was observed on the beamline near the ion source, facing the electron drift side of the PG magnetic field. It is confirmed that the experimental deflection of the negative-ion beam agrees well with the three-dimensional beam simulation result by taking account of the measured magnetic field. By using the code, it is found that some stripped electrons produced in the first acceleration gap pass through the down pitch of the multiple apertures in the next stage of acceleration grids, and then collide on the beamline around the melted location.

• OSTI ID: 20779014
• Journal Information: Review of Scientific Instruments, Vol. 77, Issue 3; Conference: 11. international conference on ion sources, Caen (France), 12-16 Sep 2005; Other Information: DOI: 10.1063/1.2170088; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATION
ANIONS
APERTURES
BEAM DYNAMICS
COMPUTERIZED SIMULATION
CURRENTS
ELECTRON DRIFT
ELECTRONS
HEATING
ION BEAMS
ION SOURCES
JT-60U TOKAMAK
MAGNETIC FIELDS
MAGNETIC FILTERS
MELTING
PLASMA
PLASMA BEAM INJECTION
PULSES
THREE-DIMENSIONAL CALCULATIONS