Construction and Operation of an Internal Coil Device, RT-1, with a High-Temperature Superconductor

• OGAWA Yuichi

  Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan

• YOSHIDA Zensho

  Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan

• MORIKAWA Junji

  Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan

• SAITO Haruhiko

  Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan

• WATANABE Sho

  Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan

• YANO Yoshihisa

  Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan

• MIZUMAKI Shoichi

  TOSHIBA corporation, Yokohama 230-0045, Japan

• TOSAKA Taizo

  TOSHIBA corporation, Yokohama 230-0045, Japan

Abstract

An internal coil device called Ring Trap-1 (RT-1) has been constructed to explore an innovative concept for a high-beta plasma based on a new relaxation theory. A high-temperature superconductor (HTS) Bi-2223 tape is employed for the internal coil of RT-1. The coil is cooled to 20 K with helium gas supplied by G-M refrigerators, and charged to a magnetomotive force of 250 kA using an external power supply. For these cooling and charging methods, we have developed several innovative techniques such as a demountable transfer tube system, persistent current switch, detachable electrode, and others. In addition, we have paid much attention to the deterioration of the HTS tape during the fabrication of the internal coil. As a result, we have demonstrated that the decay of the persistent current of the internal coil is ∼1% during 8 h. The internal coil is lifted with a levitation coil located at the upper region of the vacuum vessel. The coil position monitored with laser sensors is feedback controlled through the regulation of the levitation coil current. Stable levitation for a few hours has been demonstrated for various plasma experiments.

Journal

• Plasma and Fusion Research

  Plasma and Fusion Research 4 020-020, 2009

  The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

• internal coil device
• high temperature superconductor
• persistent current switch
• magnetic levitation
• relaxation theory
• high-beta plasma

Details

• CRID: 1390282680229998464
• NII Article ID: 130000138158
• DOI: 10.1585/pfr.4.020
• BIBCODE: 2009PFR.....4...20O
• ISSN: 18806821
• Web Site: http://www.jstage.jst.go.jp/article/pfr/4/0/4_0_020/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed