Dual Frequency ECRF System Development for JT-60SA

Kobayashi, Takayuki; Isayama, A.; Sawahata, M.; Suzuki, Satoshi; Terakado, M.; Hiranai, S.; Wada, Kenji; Sato, Yoshihiro; Hinata, J.; Yokokura, K.; Hoshino, Kazuo; Kajiwara, K.; Sakamoto, K.; Moriyama, S.

doi:10.13182/fst13-a16895

Cited by 9 publications

(6 citation statements)

References 14 publications

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“…An application of a dual-frequency gyrotron for the JT-60SA ECH/ECCD system was firstly discussed in 2010 [24]. Then, the detail design of the dual-frequency gyrotron was carried out in JAEA in 2011 [19], and the gyrotron was fabricated in Toshiba Electron Tube and Devices Co., Ltd in 2011-2012. An initial short pulse commissioning was done in early 2012.…”

Section: Development Of High-power Long-pulse Gyrotron For Two Freque...mentioning

confidence: 99%

“…where a, n w , and λ w are the radius of the cavity, an integer and the wavelength in the window material, respectively. Detail of the gyrotron design was reported in the previous work [19]. Table 1 shows a summary of the key parameters chosen for this gyrotron.…”

Section: Design Of Gyrotron Enabling Operation At Two Frequenciesmentioning

confidence: 99%

“…We found that TE 22,8 for 110 GHz with the cavity magnetic field B c of ∼4.4 T and TE 27,10 for 138 GHz with B c ∼ 5.5 T are the best combination for operation at this frequencies by careful consideration of each parameter and numerical calculations. The shape (cavity length, input and output curvature radius) of cavity resonator was optimized for chosen operating modes to obtain high efficiency at both frequencies [19]. The output power of higher than 1 MW was expected with the beam current >40 A at the acceleration voltage of 85 kV (the pitch factor of 1.1 was assumed).…”

Section: Design Of Gyrotron Enabling Operation At Two Frequenciesmentioning

confidence: 99%

“…On the other hand, the maximum B t in JT-60SA is ∼2.3 T. In this case, the higher frequency of 130-140 GHz will be more useful for heating and CD in core region of the plasma by second harmonic resonance waves. In order to enable high-power, long-pulse ECH/CD experiments in various experimental scenarios in JT-60SA, a development of ECH/CD system which can be operated at both 110 and 138 GHz has been carried out in Japan Atomic Energy Agency (JAEA) [19]. A key component to realize such system is a gyrotron for operating at both frequencies.…”

Section: Introductionmentioning

confidence: 99%

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Gyrotron development for high-power, long-pulse electron cyclotron heating and current drive at two frequencies in JT-60SA and its extension toward operation at three frequencies

et al. 2015

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A gyrotron enabling high-power, long-pulse oscillations at both 110 and 138 GHz has been developed for electron cyclotron heating (ECH) and current drive (CD) in JT-60SA. Oscillations of 1 MW for 100 s have been demonstrated at both frequencies, for the first time in the world as a gyrotron operating at two frequencies. The optimization of the anode voltage, or the electron pitch factor, using a triode gun was a key to obtain high power and high efficiency at two frequencies. It was also confirmed that the internal losses in the gyrotron were sufficiently low for expected long pulse operation at the higher power level of ∼1.5 MW. Another important result is that an oscillation at 82 GHz, which enables use of fundamental harmonic waves in JT-60SA while the other two frequencies are used as second harmonics waves, was demonstrated up to 0.4 MW for 2 s. These results of the gyrotron development significantly contribute to enhancing the operation regime of the ECH/CD system in JT-60SA.

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Section: Development Of High-power Long-pulse Gyrotron For Two Freque...mentioning

confidence: 99%

Section: Design Of Gyrotron Enabling Operation At Two Frequenciesmentioning

confidence: 99%

Section: Design Of Gyrotron Enabling Operation At Two Frequenciesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gyrotron development for high-power, long-pulse electron cyclotron heating and current drive at two frequencies in JT-60SA and its extension toward operation at three frequencies

et al. 2015

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“…Gyrotrons are powerful and essential tools for ECH and ECCD. In the 100 GHz range, dual or multifrequency MW gyrotrons are being developed in many facilities for the purpose of nuclear fusion [1][2][3][4][5][6][7][8]. At the University of Tsukuba, megawatt (MW)class gyrotrons, which cover a wide frequency range (14-300 GHz), are cur rently being developed in collaboration with several research organizations and universities, for present and future dem onstration power plant (DEMO) fusion devices, as shown in figure 1.…”

Section: Introductionmentioning

confidence: 99%

Development of high power gyrotrons for advanced fusion devices

et al. 2019

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Megawatt (MW) gyrotrons, with a wide frequency range from 14 to 300 GHz, are being developed as part of a collaborative electron cyclotron heating (ECH) study for advanced fusion devices and a demonstration power plant (DEMO). (1) Detailed designs for a 14 GHz 1 MW gyrotron are being developed for fabrication. For a 14 GHz radio frequency (RF) beam with high divergence, a calculated transmission efficiency of 94% to the corrugated waveguide coupling position was obtained initially by introducing the design concept (direct RF beam coupling by built-in waveguide) to minimize the RF transmission path. Installing a double-disk sapphire window will make it possible to develop a 1 MW gyrotron with a continuous wave (CW) at 14 GHz. (2) In experimental tests of a new 28/35 GHz dual-frequency gyrotron, the cooling characteristics of an optimal-structure double-disk sapphire window were evaluated. We confirmed that operating at 0.4 MW with a CW at 28 GHz is feasible, reaching twice the output power reported in previous studies. In a 2 ms short-pulse experimental test, maximum powers of 1.65 MW at 28.04 GHz and 1.21 MW at 34.83 GHz were achieved. (3) A design study of a 77/51 GHz dual-frequency gyrotron was performed. Oscillations above 1.5 MW for 77 GHz and 1.3 MW for 51.88 GHz are expected for a beam voltage Vk = 80 kV and beam current Ik = 60 A. (4) In an experiment with a 300 GHz gyrotron, the influence of the wave reflected from the window was reduced by tilting the output window, and mode competition in the cavity was suppressed. An output power of 0.62 MW with a pulse width of 1 ms, which is the new record for this frequency, was obtained. (5) We also performed a trial design study of a 240 GHz gyrotron for DEMO.

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