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Title: Super H-mode: theoretical prediction and initial observations of a new high performance regime for tokamak operation

Journal Article · · Nuclear Fusion
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  1. General Atomics, San Diego, CA (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. Univ. of York, Heslington, York (United Kingdom)
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A new “Super H-mode” regime is predicted, which enables pedestal height and predicted fusion performance substantially higher than for H-mode operation. This new regime is predicted to exist by the EPED pedestal model, which calculates criticality constraints for peeling-ballooning and kinetic ballooning modes, and combines them to predict the pedestal height and width. EPED usually predicts a single (“H-mode”) pedestal solution for each set of input parameters, however, in strongly shaped plasmas above a critical density, multiple pedestal solutions are found, including the standard “Hmode” solution, and a “Super H-Mode” solution at substantially larger pedestal height and width. The Super H-mode regime is predicted to be accessible by controlling the trajectory of the density, and to increase fusion performance for ITER, as well as for DEMO designs with strong shaping. A set of experiments on DIII-D has identified the predicted Super H-mode regime, and finds pedestal height and width, and their variation with density, in good agreement with theoretical predictions from the EPED model. Finally, the very high pedestal enables operation at high global beta and high confinement, including the highest normalized beta achieved on DIII-D with a quiescent edge.

Research Organization:
General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Grant/Contract Number:
FC02-04ER54698; AC02-09CH11466; FC02-06ER54873; FG02-95ER54309
OSTI ID:
1373882
Alternate ID(s):
OSTI ID: 1238961
Journal Information:
Nuclear Fusion, Vol. 55, Issue 8; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 35 works
Citation information provided by
Web of Science

References (25)

Improved understanding of physics processes in pedestal structure, leading to improved predictive capability for ITER journal August 2013
H-mode pedestal scaling in DIII-D, ASDEX Upgrade, and JET journal May 2011
A first-principles predictive model of the pedestal height and width: development, testing and ITER optimization with the EPED model journal August 2011
Limits to the H-mode pedestal pressure gradient in DIII-D journal May 2010
Impact of T e and n e on edge current density profiles in ELM mitigated regimes on ASDEX Upgrade journal December 2014
Pedestal stability comparison and ITER pedestal prediction journal July 2009
Stability and dynamics of the edge pedestal in the low collisionality regime: physics mechanisms for steady-state ELM-free operation journal August 2007
Confinement of ‘improved H-modes’ in the all-tungsten ASDEX Upgrade with nitrogen seeding journal September 2011
Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes journal May 2002
Improved performance of ELMy H-modes at high density by plasma shaping in JET journal August 2002
High confinement/high radiated power H-mode experiments in Alcator C-Mod and consequences for International Thermonuclear Experimental Reactor (ITER) Q DT  = 10 operation journal May 2011
The EPED pedestal model and edge localized mode-suppressed regimes: Studies of quiescent H-mode and development of a model for edge localized mode suppression via resonant magnetic perturbations journal May 2012
Numerical studies of edge localized instabilities in tokamaks journal April 2002
Pedestal study across a deuterium fuelling scan for high δ ELMy H-mode plasmas on JET with the carbon wall journal July 2013
Pedestal structure and stability in H-mode and I-mode: a comparative study on Alcator C-Mod journal March 2013
Edge pedestal control in quiescent H-mode discharges in DIII-D using co-plus counter-neutral beam injection journal July 2009
Development and validation of a predictive model for the pedestal height journal May 2009
The H-mode pedestal structure and its role on confinement in JET with a carbon and metal wall journal December 2014
Effects of a sheared toroidal rotation on the stability boundary of the MHD modes in the tokamak edge pedestal journal May 2009
Full linearized Fokker–Planck collisions in neoclassical transport simulations journal December 2011
MHD stability analysis of small ELM regimes in JET journal December 2008
Edge stability of stationary ELM-suppressed regimes on DIII-D journal July 2008
Characterization of peeling–ballooning stability limits on the pedestal journal April 2004
ELMs: MHD instabilities at the transport barrier journal November 2005
Access to a New Plasma Edge State with High Density and Pressures using the Quiescent H Mode journal September 2014

Cited By (1)

Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling journal May 2018

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Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
tokamak
pedestal
Super H-Mode
fusion performance
pedestal height
theoretical predictions
EPED