Internally generated currents in a small-aspect-ratio tokamak geometry

Forest, C.B.; Hwang, Y.S.; Ono, M.; Darrow, D. S.

doi:10.1103/physrevlett.68.3559

Cited by 78 publications

(80 citation statements)

References 6 publications

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“…The only experimental reference of possible bootstrap-overdrive plasma current buildup is in CDX-U [21][22]. There it is reported that the plasma bootstrap current was largely responsible for increasing the current of an a=0.2 m , T e = 30 eV plasma from 600 A to 1000 A in 10 ms.…”

Section: Relation To Experimentsmentioning

confidence: 99%

Timescales for non-inductive current buildup in low aspect ratio toroidal geometry

Jardin

2000

Nucl. Fusion

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The fundamental differences between inductive and non-inductive current buildup are clarified and the associated time-scales and other implications are discussed. A simulation is presented whereby the plasma current in a low-aspect-ratio torus is increased primarily by the self-generated bootstrap current with only 10% coming from external current drive. The maximum obtainable plasma current by this process is shown to scale with the toroidal field strength. The basic physics setting the time-scales can be obtained from a 1D analysis. Comparisons are made between the timescales found here and those reported in the experimental literature.2

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Section: Relation To Experimentsmentioning

confidence: 99%

Timescales for non-inductive current buildup in low aspect ratio toroidal geometry

Jardin

2000

Nucl. Fusion

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“…This demonstration is complicated by the intricate coupling of current drive efficiency, confinement, and MHD stability: The quality of confinement and MHD stability limit the amount of power which can be injected into the tokamak to drive current. A possible ramp-up scenario is to form a discharge noninductively [22] and then to increase the current drive power until the discharge is near, but not above the b limit. If the noninductive current exceeds the plasma current at this power level, then the plasma current will increase.…”

Section: -9007͞97͞79(3)͞427mentioning

confidence: 99%

Reduction in Neutral Beam Driven Current in a Tokamak by Tearing Modes

et al. 1997

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“…A backup alternative to inductive startup would be to utilize ECH startup similar to what was done on CDX-U [68]. The power required to generate enough current to create closed flux surfaces is of the same order as that needed for the bootstrap ramp-up described below.…”

Section: Inductive Startupmentioning

confidence: 99%

Physics basis for a spherical torus power plant

Jardin

Kessel

Ménard

et al. 2003

Fusion Engineering and Design

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The spherical torus, or low-aspect-ratio tokamak, is considered as the basis for a fusion power plant. A special class of wall-stabilized high-b high-bootstrap fraction low-aspect-ratio tokamak equilibrium are analyzed with respect to MHD stability, bootstrap current and external current drive, poloidal field system requirements, power and particle exhaust and plasma operating regime. Overall systems optimization leads to a choice of aspect ratio A0/1.6, plasma elongation k 0/3.4, and triangularity d0/0.64. The design value for the plasma toroidal b is 50%, corresponding to b N 0/7.4, (based on the toroidal b , not the total b ) which is 10% below the ideal stability limit. The bootstrap fraction of 99% greatly alleviates the current drive requirements, with tangential neutral beam injection mainly for profile control and rotation drive. The design is such that 45% of the thermal power is radiated in the plasma by Bremstrahlung and trace Krypton, with Neon in the scrapeoff layer radiating the remainder. The scarcity of spherical torus experimental data caused the design to be based largely on theoretical predictions, some of which may turn out to be overly optimistic. This highlights the need for a strong experimental research program in this area. #

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Internally generated currents in a small-aspect-ratio tokamak geometry

Cited by 78 publications

References 6 publications

Timescales for non-inductive current buildup in low aspect ratio toroidal geometry

Timescales for non-inductive current buildup in low aspect ratio toroidal geometry

Reduction in Neutral Beam Driven Current in a Tokamak by Tearing Modes

Physics basis for a spherical torus power plant

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