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Neutral Gas Compression in the Helical Divertor with a Baffle Structure in the LHD Heliotron

Suguru MASUZAKI, Masahiro KOBAYASHI, Mamoru SHOJI, Masayuki TOKITANI, Tomohiro MORISAKI, Ryuichi SAKAMOTO, Masaki OSAKABE, Takanori MURASE, Takashi KOBUCHI, Hiroaki YONEZU, Yasuhiko TAKEIRI, Hiroshi YAMADA, Akio KOMORI and the LHD Experiment Group

National Institute for Fusion Science, Oroshi 322-6, Toki 509-5292, Japan

(Received 29 November 2010 / Accepted 24 December 2010 / Published 8 February 2011)

Abstract

The helical divertor in the Large Helical Device (LHD) was partially modified before the experimental campaign in 2010 to demonstrate the ability of particle control by installing a baffle structure. The baffle structure consists of water cooled divertor plates combined with baffle plates and a dome in the private region. The neutral pressures in the modified and an existing unmodified helical divertors have been measured by using fast ion gauges during the campaign. The recycled neutral gas was successfully compressed in the modified divertor during discharges, and more than ten times higher pressure was observed there than in the unmodified divertor as expected from the neutral transport calculations.

Copyright (c) 2011 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

LHD, helical divertor, baffle structure, particle control, neutral compression, fast ion gauge

DOI: 10.1585/pfr.6.1202007

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This paper may be cited as follows:

Suguru MASUZAKI, Masahiro KOBAYASHI, Mamoru SHOJI, Masayuki TOKITANI, Tomohiro MORISAKI, Ryuichi SAKAMOTO, Masaki OSAKABE, Takanori MURASE, Takashi KOBUCHI, Hiroaki YONEZU, Yasuhiko TAKEIRI, Hiroshi YAMADA, Akio KOMORI and the LHD Experiment Group, Plasma Fusion Res. 6, 1202007 (2011).