Progress in the physics basis of a Fusion Nuclear Science Facility based on the Advanced Tokamak concept

Garofalo, A. M.; Chan, V. S.; Canik, J.; Sawan, M.E.; Choi, M.; Humphreys, D. A.; Lao, L. L.; Prater, R.; Stangeby, P.C.; John, H.E. St.; Taylor, T.S.; Turnbull, A. D.; Wong, C.P.C.

doi:10.1088/0029-5515/54/7/073015

Cited by 33 publications

(37 citation statements)

References 32 publications

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“…In the United States, the original ARIES design [9] has been updated with various 'Advanced and Conservative Tokamak' (ACT) versions [21], while proposals are also made for more compact lower power designs with ARC [22] and ST Pilot Plant [23] facilities. In addition, the AT forms the basis for various proposed fusion nuclear science testing facilities such as the Fusion Development Facility (FDF) [24] and Fusion Nuclear Science Facility (FNSF) [25][26][27] in the United States, and the China Fusion Engineering Test Reactor (CFETR) [28].…”

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confidence: 99%

DIII-D Research to Prepare for Steady State Advanced Tokamak Power Plants

et al. 2018

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We review progress made on the advanced tokamak path to fusion energy by the DIII-D National Fusion Facility (Luxon et al. in Nucl Fusion 42:614, 2002). The advanced tokamak represents a highly attractive approach for a future steady state fusion power plant. In this concept, there is a natural alignment between high pressure operation, favorable stability and transport properties, and a highly self-driven ('bootstrap') plasma current to sustain operation efficiently and without disruptions. Research on DIII-D has identified several promising plasma configurations for fully non-inductive operation with potential applications to a range of future devices, from ITER to nuclear science facilities, to compact or large scale fusion power plants. Significant progress has been made toward realizing these scenarios, with the demonstration of high b access, off-axis current drive techniques, model based profile control, and stability and ELM control in reactor relevant physics regimes. Radiative techniques have also been pioneered to develop improved compatibility with divertor requirements, and simultaneous access to high performance pedestals. Research has also developed major advances in physics understanding, validating concepts of kinetic damping of ideal MHD instabilities that enable high b operation, identifying how current profile and b influence plasma turbulence in order to validate and improve turbulent transport models, and understanding the physics of energetic particle redistribution due to Alfvénic and other instabilities. These advances have been partnered with development of a rigorous integrated modeling framework used to interpret and validate individual physics models of the various aspects of plasma behavior, and to guide development of improved regimes and upgrades. These tools are also being used to develop and validate concepts for future reactors directly. Having established these foundations, DIII-D is now undergoing a substantial upgrade to raise power, current drive, electron heating and 3-D field capabilities in order to validate this physics and test conceptual solutions in reactor-relevant physics regimes, with a goal to resolve the key scientific and technology questions to enable a decision on a future steady state fusion power plant.

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DIII-D Research to Prepare for Steady State Advanced Tokamak Power Plants

et al. 2018

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“…5,6 A Fusion Nuclear Science Facility design (FNSF-AT) uses q min > 1:4 with strong negative central shear at b N ¼ 3:7. 7 The ARIES-AT design uses q min ¼ 2:4 and b N ¼ 5:4. 8 All of these designs are based on several predicted advantages for steady-state operation at high q min .…”

Section: Introductionmentioning

confidence: 99%

Fast-ion transport in qmin>2, high-β steady-state scenarios on DIII-D

et al. 2015

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Results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high b steady-state operating scenarios with high-q min confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing b N and the noninductive current drive. However, in scenarios with q min > 2 that target the typical range of q 95 ¼ 5-7 used in next-step steady-state reactor models, Alfv en eigenmodes cause greater fast-ion transport than classical models predict. This enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable b N . In contrast, similar plasmas except with q min just above 1 have approximately classical fast-ion transport. Experiments that take q min > 3 plasmas to higher b P with q 95 ¼ 11-12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-q min scenario, the high b P cases have shorter slowing-down time and lower rb fast , and this reduces the drive for Alfv enic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, b N , and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q 95 , high-q min plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfv en eigenmodes. V C 2015 AIP Publishing LLC. [http://dx.

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“…This work presents the modeling investigation and planned experimental validation of a non-standard ECCD technique -top launch ECCD. Comparisons of top launch and conventional outside launch ECCD modelled for DEMO [9] and FNSF-AT [10] suggest that the top launch approach can substantially increase the interactions of EC waves with higher energy electrons and thus the ECCD efficiency at mid-radius. We consistently find 35% or more improvement in ECCD efficiency for CFETR [11] baseline scenario and even higher increases for some cases on the DIII-D tokamak.…”

Section: Introductionmentioning

confidence: 99%

Top Launch for Higher Off-axis Electron Cyclotron Current Drive Efficiency

et al. 2019

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Efficient off-axis current drive is crucial for economic, steady-state tokamak fusion power plants. “Top Launch” electron cyclotron current drive (ECCD) is one promising method for driving strong off-axis current to achieve the desired broad current profile for the Advanced Tokamak regime. New simulations show that by launching the electron cyclotron (EC) waves downwards (or upwards) nearly parallel to the resonance plane with a large toroidal steering, higher current drive efficiency can be obtained at large radii owing to the large Doppler shift, wave-particle interactions on HFS of the plasma, and the long absorption path. Implementations on CFETR and DIII-D are simulated identifying clear benefits and optimal configurations. The design of a prototype test being installed on DIII-D is presented, which will experimentally validate whether top launch ECCD can be an improved efficiency current drive technique for future fusion reactors.

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Progress in the physics basis of a Fusion Nuclear Science Facility based on the Advanced Tokamak concept

Cited by 33 publications

References 32 publications

DIII-D Research to Prepare for Steady State Advanced Tokamak Power Plants

DIII-D Research to Prepare for Steady State Advanced Tokamak Power Plants

Fast-ion transport in qmin>2, high-β steady-state scenarios on DIII-D

Top Launch for Higher Off-axis Electron Cyclotron Current Drive Efficiency

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Progress in the physics basis of a Fusion Nuclear Science Facility based on the Advanced Tokamak concept

Cited by 33 publications

References 32 publications

DIII-D Research to Prepare for Steady State Advanced Tokamak Power Plants

DIII-D Research to Prepare for Steady State Advanced Tokamak Power Plants

Fast-ion transport in qmin&gt;2, high-β steady-state scenarios on DIII-D

Top Launch for Higher Off-axis Electron Cyclotron Current Drive Efficiency

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Fast-ion transport in qmin>2, high-β steady-state scenarios on DIII-D