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

Isobe, M.; Shimizu, A.; Liu, Haifeng; Xiong, Guozhen; Yin, Di; Ogawa, K.; Yoshimura, Y.; Nakata, M.; Kinoshita, Shigeyoshi; Okamura, S.; Tang, C. J.; Xu, Yuhong

doi:10.1585/pfr.14.3402074

Cited by 23 publications

(26 citation statements)

References 23 publications

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“…One promising example is the Chinese First Quasi-Axisymmetric Stellarator (CFQS), a low aspect ratio device designed to combine the positive features of Tokamaks and Stellarators. CFQS targets the operation of plasma with a high β, good neoclasical transport and improved MHD stability [1,2,3,4,5,6,7].…”

Section: Introductionmentioning

confidence: 99%

Study of the Alfven eigenmodes stability in CFQS plasma using a Landau closure model

et al. 2021

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The aim of this study is to analyze the stability of the Alfven Eigenmodes (AE) in the Chinese First Quasi-Axisymmetric Stellarator (CFQS). The AE stability is calculated using the code FAR3d that solves the reduced MHD equations to describe the linear evolution of the poloidal flux and the toroidal component of the vorticity in a full 3D system, coupled with equations of density and parallel velocity moment for the energetic particles (EP) species including the effect of the helical couplings and acoustic modes. The Landau damping and resonant destabilization effects are added in the model by a given closure relation. The simulation results indicate the destabilization of n = 1 to 4 AEs by EP during the slowing down process, particularly n = 1 and n = 2 Toroidal AEs (TAE), n = 3 Elliptical AE (EAE) and n = 4 Non circular AE (NAE). If the resonance is caused by EPs with an energy above 17 keV (weakly thermalized EP), n = 2 EAEs and n = 3 NAEs are unstable. On the other hand, EPs with an energy below 17 keV (late thermalization stage) lead to the destabilization of n = 3 and n = 4 TAEs. The simulations for an off-axis NBI injection indicate the further destabilization of n = 2 to 4 AEs although the growth rate of the n = 1 AEs slightly decreases, so no clear optimization trend with respect to the NBI deposition region is identified. In addition, n = 2, 4 Helical AE (HAE) are unstable above an EP β threshold. Also, if the thermal β of the simulation increases (higher thermal plasma density) the AE stability of the plasma improves. The simulations including the effect of the Finite Larmor Radius (FLR) and electron-ion Landau damping show the stabilization of the n = 1 to 4 EAE/NAEs as well as a decrease of the growth rate and frequency of the n = 1 to 4 BAE/TAEs.

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Section: Introductionmentioning

confidence: 99%

Study of the Alfven eigenmodes stability in CFQS plasma using a Landau closure model

et al. 2021

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“…The main parameters of the CFQS are as follows: the major radius is 1 m, the magnetic field strength is 1 T, and the aspect ratio is 4 [5][6][7]. The modular coil system of the CFQS was designed by the NESCOIL code [9].…”

Section: Assumption Of Coil Misalignmentmentioning

confidence: 99%

“…The neoclassical transport property of QAS is similar to that of tokamak; however, the current drive is not required and the advantage of the steady state operation capability is retained. The Chinese first quasiaxisymmetric stellarator (CFQS) is the first experimental device of the QAS, which will be constructed in China, under the international joint project of National Institute for Fusion Science (NIFS) in Japan and Southwest Jiaotong University (SWJTU) in China [5][6][7]. The physical design for the CFQS is almost complete, and the engineering design is underway.…”

Section: Introductionmentioning

confidence: 99%

Consideration of the Influence of Coil Misalignment on the Chinese First Quasi-Axisymmetric Stellarator Magnetic Configuration

Shimizu

Liu

Kinoshita

et al. 2019

Plasma and Fusion Research

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The effects of misalignment of modular coils on various physical properties in the Chinese first quasiaxisymmetric Stellarator (CFQS) are discussed in this study. To estimate the effects quantitatively, simple assumptions are made regarding the structure of coil displacement. We consider the following three cases: displacement in radial direction (Case A), displacement in the vertical direction (Case B), and displacement by tilting (Case C). In all cases, we assume that the displacement structure has a stellarator symmetry. These assumptions are employed to calculate the change in the magnetic surfaces, rotational transform profile, magnetic well depth profile, and the effective helical ripple. Calculation results show that if the magnitude of displacement is less than 10 mm, the effects on these physical properties are small, and the good neoclassical transport property is retained.

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“…In the Max-Planck Institute of Plasma Physics (MP-IPP) in Germany, the new experiment of Wendelstein 7-X (W7-X) has started the validation of plasma confinement in the optimized magnetic configuration design (Pedersen et al 2016;Wolf et al 2017). In China, the joint project of NIFS and Southwest Jiaotong University (SWJTU) is starting to construct a new quasi-axisymmetric stellarator (CFQS) for the validation of one of the advanced stellarator concepts of quasi-axisymmetry (Xu et al 2018;Isobe et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Island divertor configuration design for a quasi-axisymmetric stellarator CFQS

et al. 2020

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A magnetic field configuration of an island divertor for a quasi-axisymmetric stellarator (CFQS) is proposed. The configuration incorporates large islands surrounding the core confinement region. The interface between the core region and the peripheral region of the island divertor is a clear magnetic separatrix similar to a tokamak divertor. The structure of divertor magnetic field lines is very regular without stochasticity and the connection length is sufficiently long for good divertor performance. Such a divertor configuration is produced in the magnetic field configuration for the CFQS device, which is now under construction in China.

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

Cited by 23 publications

References 23 publications

Study of the Alfven eigenmodes stability in CFQS plasma using a Landau closure model

Study of the Alfven eigenmodes stability in CFQS plasma using a Landau closure model

Consideration of the Influence of Coil Misalignment on the Chinese First Quasi-Axisymmetric Stellarator Magnetic Configuration

Island divertor configuration design for a quasi-axisymmetric stellarator CFQS

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