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Title: Compact antenna for two-dimensional beam scan in the JT-60U electron cyclotron heating/current drive system

Abstract

A compact antenna system was designed and fabricated to enable millimeter-wave beam scanning in the toroidal and poloidal directions of the JT-60U tokamak for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) experiments. The antenna consists of a fast movable flat mirror mounted on the tokamak vacuum vessel and a rotary focusing mirror attached at the end of the waveguide that is supported from outside the vacuum vessel. This separate support concept enables a compact structure inside a shallow port (0.68x0.54x0.2 m) that is shared with a subport for an independent diagnostic system. During a plasma shot, the flat mirror is driven by a servomotor with a 3-m-long drive shaft to reduce the influence of the high magnetic field on the motor. The focusing mirror is rotated by a simple mechanism utilizing a push rod and an air cylinder. The antenna has been operated reliably for 3 years after a small improvement to the rotary drive mechanism. It has made significant contributions to ECH and ECCD experiments, especially the current profile control in JT-60U.

Authors:
; ; ; ; ; ;  [1]
  1. Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Mukoyama 801-1, Naka-shi, Ibaraki 311-0193 (Japan)
Publication Date:
OSTI Identifier:
20723246
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 76; Journal Issue: 11; Other Information: DOI: 10.1063/1.2130967; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANTENNAS; CONTAINERS; CURRENTS; ECR CURRENT DRIVE; ECR HEATING; FOCUSING; JT-60U TOKAMAK; MAGNETIC FIELDS; MIRRORS; PLASMA; PLASMA CONFINEMENT; PLASMA DIAGNOSTICS; RF SYSTEMS

Citation Formats

Moriyama, S., Kajiwara, K., Takahashi, K., Kasugai, A., Seki, M., Ikeda, Y., and Fujii, T. Compact antenna for two-dimensional beam scan in the JT-60U electron cyclotron heating/current drive system. United States: N. p., 2005. Web. doi:10.1063/1.2130967.
Moriyama, S., Kajiwara, K., Takahashi, K., Kasugai, A., Seki, M., Ikeda, Y., & Fujii, T. Compact antenna for two-dimensional beam scan in the JT-60U electron cyclotron heating/current drive system. United States. doi:10.1063/1.2130967.
Moriyama, S., Kajiwara, K., Takahashi, K., Kasugai, A., Seki, M., Ikeda, Y., and Fujii, T. Tue . "Compact antenna for two-dimensional beam scan in the JT-60U electron cyclotron heating/current drive system". United States. doi:10.1063/1.2130967.
@article{osti_20723246,
title = {Compact antenna for two-dimensional beam scan in the JT-60U electron cyclotron heating/current drive system},
author = {Moriyama, S. and Kajiwara, K. and Takahashi, K. and Kasugai, A. and Seki, M. and Ikeda, Y. and Fujii, T.},
abstractNote = {A compact antenna system was designed and fabricated to enable millimeter-wave beam scanning in the toroidal and poloidal directions of the JT-60U tokamak for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) experiments. The antenna consists of a fast movable flat mirror mounted on the tokamak vacuum vessel and a rotary focusing mirror attached at the end of the waveguide that is supported from outside the vacuum vessel. This separate support concept enables a compact structure inside a shallow port (0.68x0.54x0.2 m) that is shared with a subport for an independent diagnostic system. During a plasma shot, the flat mirror is driven by a servomotor with a 3-m-long drive shaft to reduce the influence of the high magnetic field on the motor. The focusing mirror is rotated by a simple mechanism utilizing a push rod and an air cylinder. The antenna has been operated reliably for 3 years after a small improvement to the rotary drive mechanism. It has made significant contributions to ECH and ECCD experiments, especially the current profile control in JT-60U.},
doi = {10.1063/1.2130967},
journal = {Review of Scientific Instruments},
number = 11,
volume = 76,
place = {United States},
year = {Tue Nov 15 00:00:00 EST 2005},
month = {Tue Nov 15 00:00:00 EST 2005}
}