[Table of Contents]

Plasma and Fusion Research

Volume 5, S2003 (2010)

Regular Articles

Physics of Heliotron J Confinement
Fumimichi SANO, Tohru MIZUUCHI, Kazunobu NAGASAKI, Kiyoshi HANATANI, Hiroyuki OKADA, Yuji NAKAMURA1), Takashi MINAMI, Shinji KOBAYASHI, Satoshi YAMAMOTO, Shigeru KONOSHIMA, Shinsuke OHSHIMA2), Masaki TAKEUCHI, Yoshiyuki IJIRI, Keiji YAGUCHI, Tohru SENJU, Masashi SHIBANO, Kiyoshi TOHSHI, Kinzou SAKAMOTO, Akinobu MATSUYAMA1), Kiyofumi MUKAI1), Keishi MINAMI1), Shintarou KISHI1), Hyunyong LEE1), Yu TAKABATAKE1), Hiroaki YASHIRO1), Kento YAMAMOTO1), Kohta NOMURA1), Masashige SUWA1), Hayao YOSHINO1), Sadayoshi MURAKAMI3), Takashi MUTOH4), Yasuhiko TAKEIRI4), Kenichi NAGAOKA4), Shoichi OKAMURA4), Kiyomasa Y. WATANABE4), Masayuki YOKOYAMA4), Yasuhiro SUZUKI4), Yasuo YOSHIMURA4), Shin NISHIMURA4), Naoki TAMURA4), Satoru SAKAKIBARA4), Gen MOTOJIMA4), Nobuhiro NISHINO5), Takeshi FUKUDA6), Yousuke NAKASHIMA7), Zhen FENG8), Qingwei YANG8), Angela FERNÁNDEZ9), Alvaro CAPPA9), Victor TRIBALDOS9), Boyd D. BLACKWELL10) and Viktor V. CHECHKIN11)
Institute of Advanced Energy, Kyoto University, Kyoto 611-0011, Japan
1)
Graduate School of Energy Science, Kyoto University, Kyoto 611-0011 , Japan
2)
Kyoto University Pioneering Research Unit for Next Generation, Kyoto 611-0011, Japan
3)
Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
4)
National Institute for Fusion Science, Gifu 509-5292, Japan
5)
Graduate School of Engineering, Hiroshima University, Hiroshima 739-8527, Japan
6)
Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
7)
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
8)
Center for Fusion Science, Southwestern Institute of Physics, Sichuan 610041, China
9)
Laboratorio Nacional de Fusion, EURATOM-CIEMAT, 28040 Madrid, Spain
10)
Australian National University, Canberra, Australia
11)
Institute of Plasma Physics, NSC KIP, 61108 Kharkov, Ukraine
(Received 7 December 2009 / Accepted 12 April 2010 / Published 10 December 2010)

Abstract

This paper reviews the results of an experimental study undertaken in Heliotron J over the past few years to explore the physics design base for a new concept of a helical-axis heliotron. Measurements of electron cyclotron resonance (ECR)/neutral beam injection (NBI)/ion cyclotron range of frequencies (ICRF) heating plasmas have been made for understanding global energy confinement in connection with the international stellarator scaling law (ISS04), spontaneous confinement improvement (L-H transition), confinement improvement based on supersonic molecular beam injection (SMBI), magnetohydrodynamic (MHD) activity, edge plasma characteristics, including rotation of a filamentary turbulence structure, and plasma current control, including the electron cyclotron current drive (ECCD), the energetic-particle driven Alfvén eigenmodes, and related fast ion dynamics. The results are discussed in terms of the rotational transform ι/2π and the bumpiness εb (or the effective helical ripple εeff). Control of these two parameters was experimentally demonstrated to be the key issue in determining the optimum performance of Heliotron J. The result confirms that the helical-axis heliotron provides a unique and high potential for exploiting an alternative and advanced path to future helical systems.

Keywords

Heliotron J, helical-axis heliotron, bumpiness, stellarator, confinement improvement, L-H transition, H-mode, ISS04, MHD, ECCD, SMBI, Alfvén eigenmode, advanced helical system

DOI: 10.1585/pfr.5.S2003

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This paper may be cited as follows:

Fumimichi SANO, Tohru MIZUUCHI, Kazunobu NAGASAKI, Kiyoshi HANATANI, Hiroyuki OKADA, Yuji NAKAMURA, Takashi MINAMI, Shinji KOBAYASHI, Satoshi YAMAMOTO, Shigeru KONOSHIMA, Shinsuke OHSHIMA, Masaki TAKEUCHI, Yoshiyuki IJIRI, Keiji YAGUCHI, Tohru SENJU, Masashi SHIBANO, Kiyoshi TOHSHI, Kinzou SAKAMOTO, Akinobu MATSUYAMA, Kiyofumi MUKAI, Keishi MINAMI, Shintarou KISHI, Hyunyong LEE, Yu TAKABATAKE, Hiroaki YASHIRO, Kento YAMAMOTO, Kohta NOMURA, Masashige SUWA, Hayao YOSHINO, Sadayoshi MURAKAMI, Takashi MUTOH, Yasuhiko TAKEIRI, Kenichi NAGAOKA, Shoichi OKAMURA, Kiyomasa Y. WATANABE, Masayuki YOKOYAMA, Yasuhiro SUZUKI, Yasuo YOSHIMURA, Shin NISHIMURA, Naoki TAMURA, Satoru SAKAKIBARA, Gen MOTOJIMA, Nobuhiro NISHINO, Takeshi FUKUDA, Yousuke NAKASHIMA, Zhen FENG, Qingwei YANG, Angela FERNÁNDEZ, Alvaro CAPPA, Victor TRIBALDOS, Boyd D. BLACKWELL and Viktor V. CHECHKIN, Plasma Fusion Res. 5, S2003 (2010).