Development of new triangle fast directional switch for high power millimeter wave without frequency modulation

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06933
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Nuclear fusion studies
• Research Institution: Ibaraki University
• Principal Investigator: Saigusa Mikio 茨城大学, 理工学研究科(工学野), 教授 (10292476)
• Research Collaborator: Imai Tsuyoshi ; Takahashi Koji ; Oda Yasuhisa ; Ikeda Ryosuke ; Honzu Toshihiko ; Mori Junnya ; Shozu Hiroki ; Inoue Fumiaki ; Yokoyama Kana
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 核融合 / 電子サイクロトロン / ミリ波 / 高速スイッチ / 固定周波数 / 固有振動 / リング共振器

Outline of Final Research Achievements

A new fast directional switch for high power millimeter waves without frequency modulation was proposed for electron cyclotron current driving system in fusion reactor. The principle is the ring resonator of circular corrugated waveguide with vibrating reflectors. The operation frequency of switch can be adjusted by the thermal expansion using a precision chiller. In 2016, the switching frequency was obtained up to 600 Hz by the two synchronized vibration mirrors. In 2017, the natural vibration reflector was develop for higher frequency operation. In 2018, the new triangle switch which has smaller transmission loss and lighter weight than previous one, was developed. The basic properties of the new triangle switch were measured in low power test. The parasitic resonances were observed at large amplitude vibration of the reflector.

Free Research Field

核融合理工学

Academic Significance and Societal Importance of the Research Achievements

核融合炉の電子サイクロトロン加熱電流駆動装置用に、固定周波数でMW級大電力ミリ波の高速切換が行えるスイッチを世界で初めて開発した。まだ切換周波数は600 Hz以下までだが、kHzまでの高速切換を可能にする固有振動を利用した反射鏡のアイデアを生み出し、またスイッチのコストダウンのための小型化、冷却を容易にする低損失化も実現した。これらの成果により、大電力ミリ波源であるジャイロトロンの高圧電源のon/off運転によるプラズマの安定化実験は半分の電力で実現可能になり、将来の核融合炉の電子サイクロトロン電流駆動装置のコストは約半分にまで削減できる。