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Development of 154/116 GHz Dual-Frequency Gyrotron for the Large Helical Device

Tsuyoshi KARIYA¹⁾, Ryutaro MINAMI¹⁾, Takashi SHIMOZUMA²⁾, Satoshi ITO³⁾, Shin KUBO⁴⁾, Hiroe IGAMI²⁾, Masaki NISHIURA²⁾, Mizuki SAKAMOTO¹⁾

1)

Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan

2)

National Institute for Fusion Science, National Institutes of Natural Sciences, Gifu 509-5292, Japan

3)

ITER Organization, Heating & Current Drive Division, Saint-Paul-lez-Durance, France

4)

College of Science and Engineering, Chubu University, Aichi 487-8501, Japan

(Received 24 December 2024 / Accepted 28 January 2025 / Published 18 April 2025)

Abstract

Based on the successful results of three 77 and two 154 GHz gyrotrons development and their contributions to large helical device (LHD) plasma experiments, a new 154/116 GHz dual-frequency gyrotron was developed. The optimal combination of cavity oscillation modes for dual-frequency oscillations at 154 and 116 GHz and optimal designs for the electron gun, cavity, mode converter, RF transmission mirrors, output window, and collector were determined. In an experimental test of the 154/116 GHz dual-frequency gyrotron, maximum powers of 1.66 and 1.34 MW were achieved at 154.05 and 116.15 GHz with pulse widths of 2.5 ms, respectively.

Copyright (c) 2025 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

gyrotron, dual-frequency, MW, ECRH, LHD

DOI: 10.1585/pfr.20.1402022

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