Development of 7 T Cryogen-free Superconducting Magnet for Gyrotron

Hirose, R.; Kamikado, T.; Okui, Y.; Miyata, Hiroyuki; Ozaki, Osamu; Sakamoto, K.

doi:10.1109/tasc.2008.922296

Cited by 17 publications

(7 citation statements)

References 6 publications

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“…This is not suitable for the application of NTM stabilization for the reason explained in section 4. In 2008, the 7 T cryogen-free magnet [28] by JASTEC was able to apply 40 mT/s tuning speed in a range of ± 200 mT, corresponding to 0.96 GHz/s for a total bandwidth of approximately 9.6 GHz. The tuning speed and range of this JASTEC magnet will be considered here as typical characteristics.…”

Section: Considerations On Frequency Steptunable Gyrotronsmentioning

confidence: 99%

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Basic design considerations for a frequency step-tunable electron cyclotron wave system to suppress NTMs in DEMO

Aiello

Avramidis

et al. 2021

Fusion Engineering and Design

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An Electron Cyclotron Wave (ECW) system will be used in the European DEMO for the stabilization of Neoclassical Tearing Modes (NTMs). In order to avoid movable mirrors in the harsh environment close to the plasma and to simplify the NTM launcher integration, the tuning of the ECW deposition location can be achieved by launching frequency-tunable ECWs from fixed mirrors while the frequency is tuned in discrete steps of 2-3 GHz. An overview of the frequency step-tunable ECW system for NTM stabilization is presented. The design considerations are discussed based on the current DEMO baseline parameters and the status of technologies. A simulation of NTM stabilization with an idealized frequency tunable ECW system on an analytical NTM model is shown. The simulation takes into account a realistic tuning speed based on the present technology and considers the current NTM launcher configurations in DEMO. A simple sweeping strategy is adapted for the control of frequency. Various uncertainties, which will affect the feasibility, need to be further investigated.

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Section: Considerations On Frequency Steptunable Gyrotronsmentioning

confidence: 99%

“…• A characteristic ramping speed of 40 mT/s is assumed according to [28]. Scanning the total bandwidth would take 13 s.…”

Section: Considerations On Frequency Steptunable Gyrotronsmentioning

confidence: 99%

Basic design considerations for a frequency step-tunable electron cyclotron wave system to suppress NTMs in DEMO

Aiello

Avramidis

et al. 2021

Fusion Engineering and Design

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“…A cryogen-free SCM for fast frequency tuning has already been developed in Japan [59,130]. In this SCM, an additional superconducting sweeping coil is installed inside the main coil.…”

Section: Fast Frequency-tunable Gyrotron In Japanmentioning

confidence: 99%

High-power gyrotrons for electron cyclotron heating and current drive

Thumm¹,

Денисов²,

Sakamoto³

et al. 2019

Nucl. Fusion

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141

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In many tokamak and stellarator experiments around the globe that are investigating energy production via controlled thermonuclear fusion, electron cyclotron heating and current drive (ECH&CD) are used for plasma start-up, heating, non-inductive current drive and MHD stability control. ECH will be the first auxiliary heating method used on ITER. Megawatt-class, continuous wave (CW) gyrotrons are employed as high-power millimeter (mm)-wave sources. The present review reports on the worldwide state-of-the-art of high-power gyrotrons. Their successful development during the past years changed ECH from a minor to a major heating method. After a general introduction of the various functions of ECH&CD in fusion physics, especially for ITER, Section 2 will explain the fast-wave gyrotron interaction principle. Section 3 discusses innovations on the components of modern long-pulse fusion gyrotrons (magnetron injection electron gun (MIG), beam tunnel, cavity, quasi-optical output coupler, synthetic diamond output window, single-stage depressed collector) and auxiliary components (superconducting magnets, gyrotron diagnostics, high-power calorimetric dummy loads). Section 4 deals with present megawatt-class gyrotrons for ITER, W7-X, LHD, EAST, KSTAR and JT-60SA, and also includes tubes for moderate pulse length machines as, ASDEX-U, DIII-D, HL-2A, TCV, QUEST and GAMMA-10. In Section 5 the development of future advanced fusion gyrotrons is discussed. These are tubes with higher frequencies for DEMO, multi-frequency (multi-purpose) gyrotrons, stepwise frequency tunable tubes for plasma stabilization, injection-locked and coaxial-cavity multi-megawatt gyrotrons, as well as sub-THz gyrotrons for collective Thomson scattering (CTS). Efficiency enhancement via multi-stage depressed collectors, fast oscillation recovery methods and reliability, availability, maintainability and inspectability (RAMI) will be discussed at the end of this section.

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“…One method is to change B c . The liquid He-free super-conducting magnet (SCM) for this purpose is already developed [25,33]. In this SCM, an additional sweeping coil is installed inside the main coil.…”

Section: Fast Frequency Controlmentioning

confidence: 99%

Progress of high power 170 GHz gyrotron in JAEA

Sakamoto¹,

Kasugai²,

Kajiwara³

et al. 2009

Nucl. Fusion

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Recent progress on the high power gyrotron development in JAEA is presented. The gyrotron is featured to have a triode-type magnetron injection gun, a cylindrical resonator working at 170 GHz with TE31,8 mode, a water-cooled diamond window and a depressed collector. After the demonstration of the ITER basic performance, the gyrotron has been operated for 3 years, and recorded ∼200 GJ of total output energy. Next, a gyrotron which oscillates in higher order resonator mode, TE31,12, is designed and fabricated to study the long pulse oscillation at greater than 1 MW. In parallel, feasibility studies of a CW-power modulation for neoclassical tearing mode stabilization, a dual frequency gyrotron and a rapid frequency control are carried out. It is shown that these gyrotrons will be available with current technology.

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Development of 7 T Cryogen-free Superconducting Magnet for Gyrotron

Cited by 17 publications

References 6 publications

Basic design considerations for a frequency step-tunable electron cyclotron wave system to suppress NTMs in DEMO

Basic design considerations for a frequency step-tunable electron cyclotron wave system to suppress NTMs in DEMO

High-power gyrotrons for electron cyclotron heating and current drive

Progress of high power 170 GHz gyrotron in JAEA

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