Development Toward a Repetitive Compact Torus Injector

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

doi:10.1109/tps.2015.2499218

Cited by 10 publications

(4 citation statements)

References 20 publications

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“…The increase in the amplitude of magnetic fluctuations is due to the dominant m = 2 mode. It has been reported previously that CT injection into the CCW plasma current suppresses the m = 2 mode and does not have any effect on the m = 3 mode [6], different from the observation in the CW plasma current case.…”

Section: Resultscontrasting

confidence: 81%

“…CTI has the potential to control plasma pressure profile to optimise bootstrap current through precise control of the amount and deposition position of the fuel [5]. Also, CTI can be operated repetitively with high repetition frequency to provide a continuous and consistent fueling for fusion reactors [6]. CTI has been considered as a means to inject momentum into the tokamak plasma to control the toroidal flow.…”

Section: Introductionmentioning

confidence: 99%

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Modification of toroidal flow velocity through momentum Injection by compact torus injection into the STOR-M tokamak

et al. 2017

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In the Saskatchewan torus-modified (STOR-M) tokamak, tangential compact torus injection (CTI) experiments have been performed with normal (counter-clockwise, CCW, top view) and reversed (clockwise, CW, top view) plasma current directions while the compact torus (CT) injection direction remains in the CCW direction. The intrinsic toroidal flow direction reverses when the discharge current is reversed. However, the change in the toroidal flow direction is always toward the CTI direction (CCW). It has been determined that the momentum in high density and high velocity CT is more than ten times larger than the intrinsic toroidal rotation momentum in the typical STOR-M plasma. Therefore, the modification of the plasma toroidal rotation velocity is attributed to momentum transfer from CT to the tokamak discharge.

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Section: Resultscontrasting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Modification of toroidal flow velocity through momentum Injection by compact torus injection into the STOR-M tokamak

et al. 2017

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“…Spheromak injection into FRC plasma had already been tried and promising results were obtained, as shown in [23,24]. A single pulse of gun-fired spheromak injection can supply ~10 19 -10 20 particles and the gun can be operated with the repetition rate of > ~ 100 Hz [25]. The necessary total number of shots is ~100 shots s −1 at most.…”

Section: Heating and Fueling Of The Merged Frc To Ignitionmentioning

confidence: 99%

A DT fusion reactor design in field-reversed configuration using normal conductive coils

Hirano¹,

Sekiguchi²,

Matsumoto³

et al. 2017

Nucl. Fusion

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Assuming continued stability, favorable energy confinement time scaling, and an effective current drive and maintenance methods, a feasible DT fusion reactor design is proposed for field-reversed configuration (FRC) which uses normal conductive copper magnetic field coils at room temperature. The reactor has 3 GW fusion power, 1.5 MW m −2 neutron wall loading at the first wall, and thermal loading less than 1 MW m −2 at diverter plates. Plasma has an almost straight cylindrical shape of 40 m in length and 8.6 m in diameter. FRC can obtain very high beta (over 0.7 in average) and the magnetic field strength of the reactor will be 1.215 T, which can be produced by normal conductive coils having 70 m in length, 17.6 m in diameter, and 1.5 m in thickness with 0.6 effective conductive area ratio. Its Ohmic power loss is ~74 MW, which is less than 10% of the expected electric power output. A scenario to reach ignition from the initial formation is considered. At first, two FRCs are formed at the both ends of the reactor by fast theta-pinch with a negative bias magnetic field 6 m in length and 0.5 m in diameter. The FRCs are accelerated up to 250 km s −1 by the gradient of magnetic field strength towards the center of the burning region, collide with each other, and form a single large FRC. Their kinetic energy is converted to thermal energy, and the merged FRC is 10 m in length and 1.8 m in diameter. This FRC plasma is brought to ignition by intensive neutral beam injection (NBI) heating and particle supply. Given 200 s heating duration, the maximum NBI power is ~250 MW before alpha particle heating becomes significant. After ignition, NBI heating is not required, but there is a possibility that some part of equilibrium current must be supplied by the NBI in the MeV region.

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“…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]. Conventional fueling techniques, such as gas puffing, neutral beam injection, or pellet injection, may not be sufficient for achieving deep fueling in reactor-grade fusion plasma [3].…”

Section: Introductionmentioning

confidence: 99%

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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Development Toward a Repetitive Compact Torus Injector

Cited by 10 publications

References 20 publications

Modification of toroidal flow velocity through momentum Injection by compact torus injection into the STOR-M tokamak

Modification of toroidal flow velocity through momentum Injection by compact torus injection into the STOR-M tokamak

A DT fusion reactor design in field-reversed configuration using normal conductive coils

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

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