Investigation of energy transport in DIII-D High-<i>β</i><sub>P</sub>EAST-demonstration discharges with the TGLF turbulent and NEO neoclassical transport models

Pan, Changchun; Staebler, G. M.; Lao, L. L.; Garofalo, A. M.; Gong, Xianzu; Ren, Q.; McClenaghan, J.; Li, Guoqiang; Ding, Siye; Qian, J.; Wan, Baonian; Xu, G. S.; Solomon, W. M.; Meneghini, O.; Smith, S. P.

doi:10.1088/1741-4326/aa4ff8

Cited by 41 publications

(65 citation statements)

References 47 publications

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“…In the electromagnetic simulations it is found that ion scale turbulence suppresses electron scale fluctuations due to zonal flow mixing. A new saturation model in TGLF that incorporated this effect improved accuracy of temperature predictions, with the electromagnetic effects reducing temperature gradients, to achieve a better match to experiment as shown in Fig. 24 [74]. These effects, and discrepancies with experiment become more pronounced at higher q 95 ; there is clearly much further work to do to resolve transport models for high b advanced tokamak plasma configurations.…”

Section: Effect Of High Bmentioning

confidence: 95%

“…Experimental and modeling investigations performed in the last few years by an international joint team of scientists working on DIII-D and EAST have made great progress toward developing the high poloidal beta (eb P C 1) regime as a basis for the steady state operation of a tokamak fusion reactor [37,[69][70][71][72][73][74][75]. Plasma operation in the high poloidal beta regime ameliorates two key weakness of the tokamak configuration: current disruptions and the need for external current drive.…”

Section: High B P Scenariomentioning

confidence: 99%

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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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Section: Effect Of High Bmentioning

confidence: 95%

Section: High B P Scenariomentioning

confidence: 99%

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

et al. 2018

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“…This suggests that the that the large radius ITB and the pedestal could be coupled. However, a high pedestal state with large fluctuations in β N due to n = 1 ELMs has previously been observed with an ITB and high confinement [13] in this scenario suggesting that the ITB does not prohibit the high pedestal. To understand what role the Shafranov shift plays in sustainment of the ITB, we examine how α − s changes versus ρ, which is shown in Figure 3.…”

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confidence: 62%

Shafranov shift bifurcation of turbulent transport in the high β_p scenario on DIII-D

et al. 2019

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Shafranov shift stabilization of turbulence creates a bifurcation in transport, leading to multiple confinement states in the high βp scenario on DIII-D: An H-mode confinement state with a high edge pedestal, and a higher confinement state with a low pedestal and an internal transport barrier (ITB). The bifurcation is observed experimentally in the ion energy transport with respect to mid-radius (ρ = 0.6) pressure gradient. Here, we propose a mechanism for the often observed spontaneous transition between states and formation of an ITB at fixed βN . The high pedestal results in the plasma at large radius

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“…Note that a peak of the density fluctuation spectra near 100-130 kHz (blue curve in figure 2(c)) is the TAE activity, not the turbulence. Transport analysis for an example of discharge 154 372 suggests that the E × B shear effect is not key to the ITB formation in DIII-D high β P discharges [14]. In the analysis, the electron temperature, electron density and toroidal rotation profiles are fixed and only the ion temperature profile is predicted by TGYRO [6] with TGLF [7] for turbulent transport, and NEO [8] for neoclassical transport, to investigate the ion channel energy transport.…”

Section: Extension Of High Bootstrap Fraction Scenarios Toward Low Pl...mentioning

confidence: 99%

Advances in the high bootstrap fraction regime on DIII-D towards theQ = 5 mission of ITER steady state

et al. 2017

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Recent EAST/DIII-D joint experiments on the high poloidal beta ! regime in DIII-D have extended operation with internal transport barriers (ITBs) and excellent energy confinement (H 98y2~1 .6) to higher plasma current, for lower q 95 ≤7.0, and more balanced Neutral Beam Injection (NBI) (torque injection <2 Nm), for lower plasma rotation relative to previous results [Garofalo et al., IAEA 2014, Gong et al., IAEA 2014. Transport analysis and experimental measurements at low toroidal rotation suggest that the ExB shear effect is not key to the ITB formation in these high ! discharges. Experiments and TGLF modeling show that the Shafranov shift has a key stabilizing effect on turbulence. Extrapolation of the DIII-D results using a 0-D model shows that with the improved confinement, the high bootstrap fraction regime could achieve fusion gain Q=5 in ITER at !~2 .9 and q 95~7 . With the optimization of q(0), the required improved confinement is achievable when using 1.5-D TGLF-SAT1 for transport simulations. Results reported in this paper suggest that the DIII-D high ! scenario could be a candidate for ITER steady state operation.

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Investigation of energy transport in DIII-D High-β_PEAST-demonstration discharges with the TGLF turbulent and NEO neoclassical transport models

Cited by 41 publications

References 47 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

Shafranov shift bifurcation of turbulent transport in the high β_p scenario on DIII-D

Advances in the high bootstrap fraction regime on DIII-D towards theQ = 5 mission of ITER steady state

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Investigation of energy transport in DIII-D High-βPEAST-demonstration discharges with the TGLF turbulent and NEO neoclassical transport models

Cited by 41 publications

References 47 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

Shafranov shift bifurcation of turbulent transport in the high βp scenario on DIII-D

Advances in the high bootstrap fraction regime on DIII-D towards theQ = 5 mission of ITER steady state

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Investigation of energy transport in DIII-D High-β_PEAST-demonstration discharges with the TGLF turbulent and NEO neoclassical transport models

Shafranov shift bifurcation of turbulent transport in the high β_p scenario on DIII-D