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Title: Compatibility of internal transport barrier with steady-state operation in the high bootstrap fraction regime on DIII-D

Journal Article · · Nuclear Fusion
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  1. General Atomics, San Diego, CA (United States)
  2. Institute of Plasma Physics Chines Academy of Sciences, Anhui (People's Republic of China)
  3. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  5. Fourth State Research, Austin, TX (United States)
  6. Columbia Univ., New York, NY (United States)
  7. Univ. of California, Irvine, CA (United States)

Recent EAST/DIII-D joint experiments on the high poloidal beta tokamak regime in DIII-D have demonstrated fully noninductive operation with an internal transport barrier (ITB) at large minor radius, at normalized fusion performance increased by ≥30% relative to earlier work. The advancement was enabled by improved understanding of the 'relaxation oscillations', previously attributed to repetitive ITB collapses, and of the fast ion behavior in this regime. It was found that the 'relaxation oscillations' are coupled core-edge modes amenable to wall-stabilization, and that fast ion losses which previously dictated a large plasma-wall separation to avoid wall over-heating, can be reduced to classical levels with sufficient plasma density. By using optimized waveforms of the plasma-wall separation and plasma density, fully noninductive plasmas have been sustained for long durations with excellent energy confinement quality, bootstrap fraction ≥80%, $${{\beta}_{\text{N}}}\leqslant 4$$ , $${{\beta}_{\text{P}}}\geqslant 3$$ , and $${{\beta}_{\text{T}}}\geqslant 2\%$$ . Furthermore, these results bolster the applicability of the high poloidal beta tokamak regime toward the realization of a steady-state fusion reactor.

Research Organization:
General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Grant/Contract Number:
FC02-04ER54698; AC02-09CH11466; AC52-07NA27344; FG02-04ER54761; SC-G903402
OSTI ID:
1353118
Alternate ID(s):
OSTI ID: 1238811; OSTI ID: 1438700
Report Number(s):
LLNL-JRNL-741496
Journal Information:
Nuclear Fusion, Vol. 55, Issue 12; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 73 works
Citation information provided by
Web of Science

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Cited By (24)

On the Use of High Magnetic Field in Reactor Grade Tokamaks journal August 2018
Summary of magnetic fusion plasma physics in 1st AAPPS-DPP meeting journal March 2018
The role of zonal flows in the saturation of multi-scale gyrokinetic turbulence journal June 2016
Transport barriers in bootstrap-driven tokamaks journal May 2018
Integrated modeling of plasma ramp-up in DIII-D ITER-like and high bootstrap current scenario discharges journal April 2018
Study of Alfven eigenmodes stability in plasma with multiple NBI driven energetic particle species journal June 2019
Internal transport barrier in tokamak and helical plasmas journal January 2018
Progress of physics understanding for long pulse high-performance plasmas on EAST towards the steady-state operation of ITER and CFETR journal December 2019
A stepladder approach to a tokamak fusion power plant journal June 2017
Transport simulation of EAST long-pulse H-mode discharge with integrated modeling journal February 2018
Analysis of performance degradation in an electron heating dominant H-mode plasma after ECRH termination in EAST journal April 2018
Study of radial heat transport in W7-X using the transfer entropy journal May 2018
Analysis of Alfven eigenmode destabilization in DIII-D high poloidal β discharges using a Landau closure model journal June 2018
Subdominant modes and optimization trends of DIII-D reverse magnetic shear configurations journal February 2019
Enhanced stiffness weakening and confinement improvement by the linear electromagnetic effect in relatively high- q and low magnetic-shear plasmas journal April 2019
Analysis of Alfven eigenmode destabilization in ITER using a Landau closure model journal June 2019
Modeling and advances in the high bootstrap fraction regime on EAST towards the steady-state operation journal August 2019
Key effects on the confinement improvement of the ASDEX Upgrade hybrid scenario journal September 2019
Shafranov shift bifurcation of turbulent transport in the high β p scenario on DIII-D journal September 2019
Improved high-performance fully non-inductive discharge by optimizing the fast-ion confinement on EAST journal October 2019
The dominant micro-turbulence instabilities in the lower q 95 high β p plasmas on DIII-D and predict-first extrapolation journal November 2019
Experimental response of the divertor particle flux to internal transport barrier dynamics in EAST high- β N discharges journal January 2020
Subdominant modes and optimization trends of DIII-D reverse magnetic shear configurations text January 2019
Analysis of Alfven Eigenmode destabilization in ITER using a Landau closure model text January 2019