[Table of Contents]

Plasma and Fusion Research

Volume 3, S1031 (2008)

Regular Articles


Improvement of Ion Confinement in Core Electron-Root Confinement (CERC) Plasmas in Large Helical Device
Yasuhiko TAKEIRI, Masayuki YOKOYAMA, Kenichi NAGAOKA, Katsumi IDA, Shin KUBO, Takashi SHIMOZUMA, Hisamichi FUNABA, Masaki OSAKABE, Katsunori IKEDA, Katsuyoshi TSUMORI, Yashihide OKA, Mikiro YOSHINUMA, Shigeru MORITA, Motoshi GOTO, Kazumichi NARIHARA, Ichihiro YAMADA, Kenji TANAKA, Osamu KANEKO, Akio KOMORI and LHD Experimental Group
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
(Received 25 November 2007 / Accepted 7 March 2008 / Published 4 August 2008)

Abstract

An increase in ion temperature has been observed with superposition of centrally focused electron cyclotron resonance heating (ECRH) to plasmas heated by high-energy neutral beam injection (NBI) in Large Helical Device. The ion-temperature (Ti) rise is accompanied by the formation of electron internal transport barrier (ITB). A transport analysis shows that ion transport as well as electron transport is improved with the reduction of anomalous transport. A neoclassical ambipolar flux calculation shows a positive radial-electric field (Er) in the region of the Ti rise, and Er should suppress the enhancement of ripple transport due to the Ti-rise. These analyses indicate the ion transport improvement in the core electron-root confinement plasmas. Toroidal rotation is driven in the co-direction by applying ECRH, and the toroidal rotation velocity is increased with the Ti rise. A correlation between the Ti rise and toroidal rotation is suggested.


Keywords

core electron-root confinement, neoclassical transport, anomalous transport, radial electric field, ion transport, toroidal rotation, electron internal transport barrier

DOI: 10.1585/pfr.3.S1031


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This paper may be cited as follows:

Yasuhiko TAKEIRI, Masayuki YOKOYAMA, Kenichi NAGAOKA, Katsumi IDA, Shin KUBO, Takashi SHIMOZUMA, Hisamichi FUNABA, Masaki OSAKABE, Katsunori IKEDA, Katsuyoshi TSUMORI, Yashihide OKA, Mikiro YOSHINUMA, Shigeru MORITA, Motoshi GOTO, Kazumichi NARIHARA, Ichihiro YAMADA, Kenji TANAKA, Osamu KANEKO, Akio KOMORI and LHD Experimental Group, Plasma Fusion Res. 3, S1031 (2008).