Improvement of uniformity of the negative ion beams by tent-shaped magnetic field in the JT-60 negative ion source

Journal Article · Sat Feb 15 00:00:00 EST 2014 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4830365· OSTI ID:22253868

Yoshida, Masafumi; Hanada, Masaya; Kojima, Atsushi; Kashiwagi, Mieko; Akino, Noboru; Endo, Yasuei; Komata, Masao; Mogaki, Kazuhiko; Nemoto, Shuji; Ohzeki, Masahiro; Seki, Norikazu; Sasaki, Shunichi; Shimizu, Tatsuo; Terunuma, Yuto ^[1]; Grisham, Larry R. ^[2]

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1. Japan Atomic Energy Agency, 801-1, Mukoyama, Naka 311-0193 (Japan)
2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

Non-uniformity of the negative ion beams in the JT-60 negative ion source with the world-largest ion extraction area was improved by modifying the magnetic filter in the source from the plasma grid (PG) filter to a tent-shaped filter. The magnetic design via electron trajectory calculation showed that the tent-shaped filter was expected to suppress the localization of the primary electrons emitted from the filaments and created uniform plasma with positive ions and atoms of the parent particles for the negative ions. By modifying the magnetic filter to the tent-shaped filter, the uniformity defined as the deviation from the averaged beam intensity was reduced from 14% of the PG filter to ∼10% without a reduction of the negative ion production.

• OSTI ID: 22253868
• Journal Information: Review of Scientific Instruments, Vol. 85, Issue 2; Conference: ICIS 2011: 14. international conference on ion sources, Giardini-Naxos, Sicily (Italy), 12-16 Sep 2011; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANIONS
CATIONS
ION BEAMS
JT-60 TOKAMAK
MAGNETIC FIELDS
MAGNETIC FILTERS
PLASMA