International Journal of Terahertz Science and Technology
  TST >> Vol.8, No.1, March 2015: PP. 1-18
 

(Invited paper)Development of high power gyrotron and related technologies

Keishi Sakamoto *, Yasuhisa Oda, Ryosuke Ikeda, Takayuki Kobayashi, Ken Kajiwara, Koji Takahashi and Shinichi Moriyama
Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki, Japan 311-0193
* Email: sakamoto.keishi@jaea.go.jp

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Abstract: The research and development activities of high-power gyrotrons in JAEA for the use in nuclear fusion applications are reported. ITER requires 170 GHz 1 MW gyrotrons which are currently under development. High order modes of a cylindrical resonator to serve as oscillation mode candidates for 1 MW/ 170 GHz CW operation are studied. TE31,8 mode has shown the best performance operation, e.g., 1 MW/ 800 s/ 55% and 0.8 MW/1 hr/57%. Even higher modes are attempted to increase power. At the present stage, in TE31,11 mode, 1.24 MW/2s and 0.5 MW/1000 s have been achieved. This 170 GHz/TE31,11 mode has excellent characteristics for multi-frequency operation. By controlling resonant magnetic field and pitch factor of the electron beam, Gaussian power output was demonstrated at 203 GHz, 170 GHz, 137 GHz and 104 GHz. An anode control method was studied as a possible advantage operation scenario. A 5 kHz 1 MW full-power modulation for the plasma instability suppression was successfully demonstrated at 170 GHz by the fast of-off control of the anode voltage. A fast frequency switching of the gyrotron was studied for the power deposition profile control in the tokamak plasma, and the switching between 170 GHz and 167 GHz was proved with 3.5 s using the super-conducting sweeping coil. Furthermore, dual frequency 138 GHz/110 GHz gyrotron was developed for the application in the EC heating and current drive system of the JT-60SA tokamak. Power outputs of 1 MW/100 s were demonstrated at both frequencies. High power experiments of the transmission line and launcher were carried out using the gyrotron as a power source.

Keywords: High power gyrotron, Multi-frequency, Fast frequency switching, Power modulation.

Received: 2015-3-25

Published: 2015-3-31

Cite this article:
Keishi Sakamoto, Yasuhisa Oda, Ryosuke Ikeda, Takayuki Kobayashi, Ken Kajiwara, Koji Takahashi and Shinichi Moriyama. Development of high power gyrotron and related technologies[J]. International Journal of Terahertz Science and Technology, 2015, Vol.8, No.1: 1-18.  DOI:10.11906/TST.001-018.2015.03.01

URL: http://www.tstnetwork.org/10.11906/TST.001-018.2015.03.01

 

 
 

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