Design and implementation of fast charging circuit for repetitive compact torus injector

Onchi, Takumi; McColl, D.; Dreval, M.; Wolfe, S.; Xiao, Chunsheng; Hirose, Akira

doi:10.1016/j.fusengdes.2014.06.019

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…The travel time of the CT in the vacuum magnetic field region is excessively long, and the frequent alignment of the CT and tokamak magnetic field lines may lead to a significant depletion of the fuel particles and kinetic energy in the CT. As discussed above, there are several viewpoints regarding the estimation of the magnetic reconnection timescale. In the design of the CT, magnetic reconnection processes are considered as a secondary effect compared to the magnetic field gradient force [1,20,41]. It is worth noting that the magnetic reconnection is crucial for the deposition of fueling particles by CT injection in fusion plasmas.…”

Section: Ct Trajectory and Penetration Parametersmentioning

confidence: 99%

“…Secondly, by selecting an appropriate injection angle and velocity, it becomes possible to finely tune the timing of the CT's reconnection with the tokamak's magnetic field and its penetration time. This may also help prevent the distortion and eventual tearing of tokamak magnetic field lines, as mentioned in reference [1]. Lastly, the substantial tangential momentum carried by CT particles can be harnessed to drive current or generate plasma toroidal rotation [4,15,34].…”

Section: Tangential Injectionmentioning

confidence: 99%

“…Steady-state high-performance discharges in fusion reactors, such as the International Thermonuclear Experimental Reactor (ITER), necessitate optimized density and pressure profiles to maintain plasma confinement [1]. One potential approach for controlling these profiles involves using an adaptable fueling system capable of varying the mass density and velocity of fuel particles [2].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma

DONG 董,

ZHANG 张,

LAN 兰

et al. 2024

Plasma Sci. Technol.

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The trajectory of the compact torus (CT) within a tokamak discharge is crucial to fueling. In this study, we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tokamak discharges. This model was used to calculate the trajectory and penetration parameters of CT injections by applying both perpendicular and tangential injection schemes in both HL-2A and ITER tokamaks. For perpendicular injection along the tokamak's major radius direction from the outboard, CTs with the same injection parameters exhibited an 0.08 reduction in relative penetration depth when injected into HL-2A and a 0.13 reduction when injected into ITER geometry when considering the vacuum magnetic field region compared with cases where this region was not considered. In addition, we proposed an optimization method for determining the CT's initial injection velocity to accurately calculate the initial injection velocity of CTs for central fueling in tokamaks. Furthermore, this paper discusses schemes for the tangential injection of CT into tokamak discharges. The optimal injection angle and CT magnetic moment direction for injection into both HL-2A and ITER were determined through numerical simulations. Finally, the kinetic energy loss occurring when the CT penetrated the vacuum magnetic field region in ITER was reduced by ΔEk=975.08J by optimizing the injection angle for the CT injected into ITER. These results provided valuable insights for optimizing injection angles in fusion experiments. Our model closely represents actual experimental scenarios and can assist the design of CT parameters.

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Section: Ct Trajectory and Penetration Parametersmentioning

confidence: 99%

Section: Tangential Injectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma

DONG 董,

ZHANG 张,

LAN 兰

et al. 2024

Plasma Sci. Technol.

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“…In the future, repetitive CT fuelling of a steady-state ST plasma will be developed on QUEST. For this purpose, a fast charging circuit designed and demonstrated by the University of Saskatchewan group [41] will be used.…”

Section: Advanced Fuelling By Compact Toroid Injectionmentioning

confidence: 99%

Overview of spherical tokamak research in Japan

et al. 2017

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Nationally coordinated research on spherical tokamak is being conducted in Japan. Recent achievements include: (i) plasma current start-up and ramp-up without the use of the central solenoid by RF waves (in electron cyclotron and lower hybrid frequency ranges), (ii) plasma current start-up by AC Ohmic operation and by coaxial helicity injection, (iii) development of an advanced fuelling technique by compact toroid injection, (iv) ultra-long-pulse operation and particle control using a high temperature metal wall, (v) access to the ultra-high-β regime by high-power reconnection heating, and (vi) improvement of spherical tokamak plasma stability by externally applied helical field.

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“…and are especially relevant to the morphology of solar eruptions. Furthermore, other plasma experiments that use FGVs (Hansen & Bellan 2001;Milanese et al 2006;Stenson & Bellan 2012;Suzuki-Vidal et al 2013;Onchi et al 2014;Raman et al 2014;Tenfelde et al 2014;Loebner et al 2015;Ha & Bellan 2016) should be aware of the potential for nonlinear interaction between multiple gas valves.…”

Section: Introductionmentioning

confidence: 99%

Apex Dips of Experimental Flux Ropes: Helix or Cusp?

Wongwaitayakornkul

Haw

et al. 2017

ApJ

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We present a new theory for the presence of apex dips in certain experimental flux ropes. Previously such dips were thought to be projections of a helical loop axis generated by the kink instability. However, new evidence from experiments and simulations suggest that the feature is a 2D cusp rather than a 3D helix. The proposed mechanism for cusp formation is a density pileup region generated by nonlinear interaction of neutral gas cones emitted from fast-gas nozzles. The results indicate that density perturbations can result in large distortions of an erupting flux rope, even in the absence of significant pressure or gravitational forces. The density pileup at the apex also suppresses the m=1 kink mode by acting as a stationary node. Consequently, more accurate density profiles should be considered when attempting to model the stability and shape of solar and astrophysical flux ropes.

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Design and implementation of fast charging circuit for repetitive compact torus injector

Cited by 8 publications

References 15 publications

Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma

Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma

Overview of spherical tokamak research in Japan

Apex Dips of Experimental Flux Ropes: Helix or Cusp?

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