Engineering Design Study of Quasi-Axisymmetric Stellarator with Low Aspect Ratio

Matsuoka, K.; Okamura, S.; Nishimura, Satoshi; Isobe, M.; Suzuki, C.; Shimizu, A.; Tanaka, Nobuo; Hasegawa, Mitsuru; Naito, H.; Urata, K.; Suzuki, Yutaka; Tsukamoto, Tadanori

doi:10.13182/fst04-a577

Cited by 7 publications

(7 citation statements)

References 7 publications

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“…The large minor radius is required to achieve above plasma parameters, so an aspect ratio (A p ) of 4 and a toroidal periodic number (N p ) of 2 were chosen. The MHD equilibrium of the CFQS was designed based on the CHS-qa [14][15][16][17]. The A p of 4 is very low among stellarators in the world, and this low aspect ratio brings challenging issues in the engineering design of magnetic field coils and support structures.…”

Section: Physics Properties Of the Cfqsmentioning

confidence: 99%

Recent developments in engineering design for the quasi-axisymmetric stellarator CFQS

et al. 2021

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A quasi-axisymmetric stellarator, the CFQS, has been designed as a joint project of the National Institute for Fusion Science and Southwest Jiaotong University to prove intrinsic advantages of quasi-axisymmetry. Principal parameters of the CFQS are as follows: the major radius is 1 m, the magnetic field strength is 1 T, the aspect ratio is 4, and the toroidal periodic number is 2. The magnetic field configuration is designed based on that of the CHS-qa. Enhanced confinement properties within the context of neoclassical theory are achieved by its quasi-axisymmetric configuration. In the entire radial range, the magnetic well is retained to keep favourable stability features in the magnetohydrodynamic equilibrium. A magnetic field coil system was designed for the CFQS, which consists of 16 modular coils, 12 toroidal field coils, and 4 poloidal field coils. The supporting structure is designed to withstand strong electromagnetic force under 1 T operation, maintaining enough space for heating and diagnostic systems. The mock-up modular coil with the most complicated shape was constructed by Hefei Keye Electro Physical Equipment Manufacturing Co., Ltd. to check manufacturability and the achieved accuracy. A heat-run test was performed to check the temperature rise of conductors, and the capability of 1 T operation was confirmed. After various tests for the mock-up coil, construction of actual modular coils and the vacuum vessel has begun.

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Section: Physics Properties Of the Cfqsmentioning

confidence: 99%

Recent developments in engineering design for the quasi-axisymmetric stellarator CFQS

et al. 2021

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“…SWJTU prepares the experiment building, basic components of the CFQS, such as magnetic field coils, vacuum chamber, power supply, pure water cooling system, and other components necessary for the CFQS operation at SWJTU. NIFS provides the basic design of the CFQS, such as magnetic field configuration, modular coil geometry, and other design matters, based on experience in physics and engineering design of the CHS-qa [9][10][11][12][13]. NIFS also provides experts to support the equipment design and machine construction, and utilizes as many unused CHS apparatuses as possible for the CFQS.…”

Section: Nifs-swjtu Joint Project For Cfqsmentioning

confidence: 99%

“…Compact Helical System (CHS)-qa as a post-CHS [9][10][11][12][13] and the National Compact Stellarator Experiment (NCSX) [14][15][16][17] based on a quasi-axisymmetry concept were intensively carried out around 2000 in the National Institute for Fusion Science (NIFS), Japan and the Princeton Plasma Physics Laboratory, United States, respectively. Also, the Evolutive Stellarator of Lorraine (ESTELL) was proposed later in France [18,19].…”

Section: Introductionmentioning

confidence: 99%

Current Status of NIFS-SWJTU Joint Project for Quasi-Axisymmetric Stellarator CFQS

Isobe

Shimizu

Liu

et al. 2019

Plasma and Fusion Research

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The world's newest quasi-axisymmetric stellarator CFQS is constructed as a joint project of the National Institute for Fusion Science, Japan and Southwest Jiaotong University, the People's Republic of China. The project is named "NSJP for CFQS". The CFQS has a major radius of 1 m, toroidal periods of 2, and aspect ratio of 4. The toroidal magnetic field strength will be increased up to 1 T. The CFQS equilibrium is characterized by low-aspect ratio and quasi-axisymmetry, having both natures of two-dimensional tokamak and three-dimensional stellarator. The CFQS offers new opportunities and fields to increase understanding of toroidal fusion plasmas.

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“…The quasi-axisymmetric stellarator CFQS was designed based on the CHS-qa [22][23][24][25], and is now under construction under a joint project of the National Institute for Fusion Science, Japan and Southwest Jiaotong University, China [26][27][28][29][30]. The CFQS magnetic configuration is characterized by low toroidal viscosity like that of a tokamak.…”

Section: Introductionmentioning

confidence: 99%

Feasibility study of heavy ion beam probe in CFQS quasi-axisymmetric stellarator

et al. 2022

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The world’s first quasi-axisymmetric stellarator, CFQS, is now under construction. The CFQS will be dedicated to studies on the interaction between flow and turbulence, and confinement improvement by suppression of turbulence in connection with proof-of-principle experiment of quasi-axisymmetry. In order to conduct this experimental research, a heavy ion beam probe (HIBP) system is planned to be installed and utilized to measure the radial electric field and its fluctuation in a CFQS plasma. In this paper, an orbit calculation for a probe beam is performed to verify feasibility of the HIBP in the CFQS. The required beam energy, possible ion species, and the observable region in a CFQS plasma are investigated. The beam attenuation by a CFQS plasma is also estimated for different beam ion species. If we use 133Cs+ as a primary probe beam, the required beam energy is expected to be 30∼50 keV, which is relatively easy to handle. In this case the beam attenuation, evaluated by the ratio between the injected and detected beam currents, is 10−3∼10−2 in a CFQS plasma with a line-averaged electron density of <1.0 × 1019 m−3. For a higher density plasma, usage of 85Rb+ is better in terms of low-beam-attenuation, and a high signal-to-noise ratio. The HIBP in the CFQS will provide a great opportunity to study physics experimentally, related to the radial electric field, poloidal flow, and turbulence suppression.

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Engineering Design Study of Quasi-Axisymmetric Stellarator with Low Aspect Ratio

Cited by 7 publications

References 7 publications

Recent developments in engineering design for the quasi-axisymmetric stellarator CFQS

Recent developments in engineering design for the quasi-axisymmetric stellarator CFQS

Current Status of NIFS-SWJTU Joint Project for Quasi-Axisymmetric Stellarator CFQS

Feasibility study of heavy ion beam probe in CFQS quasi-axisymmetric stellarator

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