Multi-Frequency, MW-Power Triode Gyrotron Having a Uniform Directional Beam

Ikeda, Ryosuke; Oda, Y.; Kobayashi, Takayuki; Kajiwara, K.; Terakado, M.; Takahashi, Koji; Moriyama, S.; Sakamoto, K.

doi:10.1007/s10762-016-0348-8

Cited by 19 publications

(19 citation statements)

References 10 publications

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“…Modern multi-frequency megawatt-class gyrotrons can operate at several frequencies in the millimeter wave range [1][2][3][4]. These frequencies correspond to the various transmission maxima of their single-disk chemical vapor deposition (CVD) diamond window.…”

Section: Introductionmentioning

confidence: 99%

A Compact Two-Frequency Notch Filter for Millimeter Wave Plasma Diagnostics

Wágner

Kasparek

Leuterer

et al. 2020

J Infrared Milli Terahz Waves

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Sensitive millimeter wave diagnostics in magnetic confinement plasma fusion experiments need protection from gyrotron stray radiation in the plasma vessel. Modern electron cyclotron resonance heating (ECRH) systems take advantage of multi-frequency gyrotrons. This means that the frequency band of some millimeter wave diagnostics contains more than one narrow-band gyrotron-frequency line, which needs to be effectively suppressed. A compact standard waveguide notch filter based on coupled waveguide resonators with rectangular cross-section is presented which can provide very high suppression of several gyrotron frequencies and has low insertion loss of the passband.

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Section: Introductionmentioning

confidence: 99%

A Compact Two-Frequency Notch Filter for Millimeter Wave Plasma Diagnostics

Wágner

Kasparek

Leuterer

et al. 2020

J Infrared Milli Terahz Waves

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“…The development of multi-frequency gyrotrons in QST (formerly JAEA) was firstly reported on a gyrotron development for ITER. The gyrotron demonstrated oscillation at both 170 GHz and 137 GHz in 2011 [23], and it was extended to quad frequency in 2016 with the addition of 104 GHz and 203 GHz [24,25].Transmission efficiencies of 94%-95% at the lower three frequencies were demonstrated in 2018 [26].…”

Section: The Multi-frequency Gyrotron Developmentmentioning

confidence: 99%

Development of high-power, long-pulse, multi-frequency ECH/CD system for JT-60SA

Kobayashi¹,

Yamazaki²,

Hiranai³

et al. 2022

Nucl. Fusion

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A gyrotron and a matching optics unit (MOU) for the multi-frequency electron cyclotron heating and current drive (ECH/CD) system in JT-60SA have been developed successfully. The gyrotron demonstrated stable operation at high powers of 1.5 MW for 5 s and 1.9 MW for 1 s at 110 GHz. To obtain high HE11 mode purity (> 90%) at the outlet of the waveguide in the ECH/CD launcher, a MOU for operating at three frequencies of 82 GHz, 110 GHz, and 138 GHz that includes three pairs of water-cooled phase correcting mirrors has been developed, which allows the mirrors to be changed without opening the evacuated MOU. The mode purity at the inlet of a dummy load in the transmission line was evaluated at high-power and an HE11 mode purity of > 90% was obtained at three frequencies.

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“…This allows various start-up scenarios to reach the nominal values of electron beam parameters. The detailed analysis of a triode-type start-up scenario has been discussed in [17][18] and experimental verification is presented in [19][20]. At specific beam energy, the corresponding value of modulating anode voltage to have a specific velocity ratio can be calculated using [17]…”

Section: Triode-type Start-up Scenariomentioning

confidence: 99%

Mode competition control using triode-type start-up scenario for a 236 GHz gyrotron for DEMO

Kalaria

Avramidis

Gantenbein

et al. 2018

2018 11th German Microwave Conference (GeMiC)

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After ITER, the first real prototype of a fusion power plant is foreseen. It is named Demonstration Power Plant (DEMO). Within the EUROfusion work package "Heating and Current Drive", the conceptual designs of both a hollow-cavity and coaxial-cavity gyrotron for DEMO has been suggested. For DEMO, the major target is to achieve an output power per tube which is significantly larger than 1 MW CW at an operating frequency of up to 240 GHz. In the case of the hollow-cavity gyrotron design, a very high-order TE mode (eigenvalue > 103 at a cutoff frequency of 236 GHz) is the prerequisite for the targeted high output power. At this eigenvalue range, the excitation of the desired operating mode during gyrotron start-up becomes challenging due to a large number of competing modes. In this work, it is demonstrated by numerical simulation that mode excitation and mode competition control can be significantly facilitated by using special start-up scenarios, based on a triode electron gun.

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Multi-Frequency, MW-Power Triode Gyrotron Having a Uniform Directional Beam

Cited by 19 publications

References 10 publications

A Compact Two-Frequency Notch Filter for Millimeter Wave Plasma Diagnostics

A Compact Two-Frequency Notch Filter for Millimeter Wave Plasma Diagnostics

Development of high-power, long-pulse, multi-frequency ECH/CD system for JT-60SA

Mode competition control using triode-type start-up scenario for a 236 GHz gyrotron for DEMO

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