New Power Records of Sub-Terahertz Gyrotron with Second-Harmonic Oscillation

Teruo SAITO; Shinya OGASAWARA; Naoki YAMADA; Shinji IKEUCHI; Yoshinori TATEMATSU; Ryosuke IKEDA; Isamu OGAWA; Vladimir N. MANUILOV

doi:10.1585/pfr.7.1206003

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New Power Records of Sub-Terahertz Gyrotron with Second-Harmonic Oscillation

Teruo SAITO, Shinya OGASAWARA, Naoki YAMADA, Shinji IKEUCHI, Yoshinori TATEMATSU, Ryosuke IKEDA, Isamu OGAWA, Vladimir N. MANUILOV

Author information

Teruo SAITO
Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
Shinya OGASAWARA
Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8463, Japan
Naoki YAMADA
Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
Shinji IKEUCHI
Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
Yoshinori TATEMATSU
Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
Ryosuke IKEDA
Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
Isamu OGAWA
Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
Vladimir N. MANUILOV
Nizhny Novgorod State University, Nizhny Novgorod 603600, Russia

Keywords: terahertz gyrotron, second-harmonic oscillation, single-mode oscillation, mode competition, collective Thomson scattering

JOURNAL FREE ACCESS

2012 Volume 7 Pages 1206003

DOI https://doi.org/10.1585/pfr.7.1206003

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Abstract

High-power sub-terahertz pulse gyrotrons are under development in FIR FU for application to collective Thomson scattering (CTS) measurement on fusion plasmas, especially on high-density plasmas such as those produced in LHD. Recently, we achieved a new power record of 62 kW at approximately 388 GHz with second-harmonic (SH) oscillation. Following this result, we modified the electron gun of the gyrotron to couple the electron beam more strongly to another oscillation mode that has a peak coupling coefficient two times as large as that of the 62 kW mode. Oscillation tests with the new mode attained higher power of 83 kW at about 389 GHz. These results constitute new second-harmonic-oscillation power records for sub-terahertz gyrotrons.

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