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

Snyder, Philip B.; Solomon, Wayne M.; Burrell, Keith H.; Garofalo, Andrea M.; Grierson, Brian A.; Groebner, Richard J.; Leonard, Anthony W.; Nazikian, Raffi; Osborne, Thomas H.; Belli, Emily A.; Candy, John; Wilson, Howard R.

doi:10.1088/0029-5515/55/8/083026

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

Abstract

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.

Authors:

Snyder, Philip B. ^[1]; Solomon, Wayne M. ^[2]; Burrell, Keith H. ^[1]; Garofalo, Andrea M. ^[1]; Grierson, Brian A. ^[2]; Groebner, Richard J. ^[1]; Leonard, Anthony W. ^[1]; Nazikian, Raffi ^[2]; Osborne, Thomas H. ^[1]; Belli, Emily A. ^[1]; Candy, John ^[1]; Wilson, Howard R. ^[3]

General Atomics, San Diego, CA (United States)
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Univ. of York, Heslington, York (United Kingdom)

Publication Date:: Tue Jul 21 00:00:00 EDT 2015

Research Org.:: General Atomics, San Diego, CA (United States)

Sponsoring Org.:: USDOE Advanced Research Projects Agency - Energy (ARPA-E)

OSTI Identifier:: 1373882

Alternate Identifier(s):: OSTI ID: 1238961

Grant/Contract Number:: FC02-04ER54698; AC02-09CH11466; FC02-06ER54873; FG02-95ER54309

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Fusion

Additional Journal Information:: Journal Volume: 55; Journal Issue: 8; Journal ID: ISSN 0029-5515

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

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

Citation Formats


                    Snyder, Philip B., Solomon, Wayne M., Burrell, Keith H., Garofalo, Andrea M., Grierson, Brian A., Groebner, Richard J., Leonard, Anthony W., Nazikian, Raffi, Osborne, Thomas H., Belli, Emily A., Candy, John, and Wilson, Howard R. Super H-mode: theoretical prediction and initial observations of a new high performance regime for tokamak operation.  United States: N. p., 2015. 
Web.  doi:10.1088/0029-5515/55/8/083026.

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                    Snyder, Philip B., Solomon, Wayne M., Burrell, Keith H., Garofalo, Andrea M., Grierson, Brian A., Groebner, Richard J., Leonard, Anthony W., Nazikian, Raffi, Osborne, Thomas H., Belli, Emily A., Candy, John, & Wilson, Howard R. Super H-mode: theoretical prediction and initial observations of a new high performance regime for tokamak operation.  United States.  https://doi.org/10.1088/0029-5515/55/8/083026

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                    Snyder, Philip B., Solomon, Wayne M., Burrell, Keith H., Garofalo, Andrea M., Grierson, Brian A., Groebner, Richard J., Leonard, Anthony W., Nazikian, Raffi, Osborne, Thomas H., Belli, Emily A., Candy, John, and Wilson, Howard R. Tue .  
"Super H-mode: theoretical prediction and initial observations of a new high performance regime for tokamak operation".  United States.  https://doi.org/10.1088/0029-5515/55/8/083026.  https://www.osti.gov/servlets/purl/1373882.

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@article{osti_1373882,

  title        = {Super H-mode: theoretical prediction and initial observations of a new high performance regime for tokamak operation},

  author       = {Snyder, Philip B. and Solomon, Wayne M. and Burrell, Keith H. and Garofalo, Andrea M. and Grierson, Brian A. and Groebner, Richard J. and Leonard, Anthony W. and Nazikian, Raffi and Osborne, Thomas H. and Belli, Emily A. and Candy, John and Wilson, Howard R.},

  abstractNote = {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.},

  doi          = {10.1088/0029-5515/55/8/083026},

  journal      = {Nuclear Fusion},

  number       = 8,

  volume       = 55,

  place        = {United States},

  year         = {Tue Jul 21 00:00:00 EDT 2015},

  month        = {Tue Jul 21 00:00:00 EDT 2015}

}

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Works referenced in this record:

Improved understanding of physics processes in pedestal structure, leading to improved predictive capability for ITER
journal, August 2013

Groebner, R. J.; Chang, C. S.; Hughes, J. W.
Nuclear Fusion, Vol. 53, Issue 9
DOI: 10.1088/0029-5515/53/9/093024

H-mode pedestal scaling in DIII-D, ASDEX Upgrade, and JET
journal, May 2011

Beurskens, M. N. A.; Osborne, T. H.; Schneider, P. A.
Physics of Plasmas, Vol. 18, Issue 5
DOI: 10.1063/1.3593008

A first-principles predictive model of the pedestal height and width: development, testing and ITER optimization with the EPED model
journal, August 2011

Snyder, P. B.; Groebner, R. J.; Hughes, J. W.
Nuclear Fusion, Vol. 51, Issue 10
DOI: 10.1088/0029-5515/51/10/103016

Limits to the H-mode pedestal pressure gradient in DIII-D
journal, May 2010

Groebner, R. J.; Snyder, P. B.; Osborne, T. H.
Nuclear Fusion, Vol. 50, Issue 6
DOI: 10.1088/0029-5515/50/6/064002

Impact of T _e and n _e on edge current density profiles in ELM mitigated regimes on ASDEX Upgrade
journal, December 2014

Dunne, M. G.; Rathgeber, S.; Burckhart, A.
Nuclear Fusion, Vol. 55, Issue 1
DOI: 10.1088/0029-5515/55/1/013013

Pedestal stability comparison and ITER pedestal prediction
journal, July 2009

Snyder, P. B.; Aiba, N.; Beurskens, M.
Nuclear Fusion, Vol. 49, Issue 8
DOI: 10.1088/0029-5515/49/8/085035

Stability and dynamics of the edge pedestal in the low collisionality regime: physics mechanisms for steady-state ELM-free operation
journal, August 2007

Snyder, P. B.; Burrell, K. H.; Wilson, H. R.
Nuclear Fusion, Vol. 47, Issue 8
DOI: 10.1088/0029-5515/47/8/030

Confinement of ‘improved H-modes’ in the all-tungsten ASDEX Upgrade with nitrogen seeding
journal, September 2011

Schweinzer, J.; Sips, A. C. C.; Tardini, G.
Nuclear Fusion, Vol. 51, Issue 11
DOI: 10.1088/0029-5515/51/11/113003

Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes
journal, May 2002

Snyder, P. B.; Wilson, H. R.; Ferron, J. R.
Physics of Plasmas, Vol. 9, Issue 5
DOI: 10.1063/1.1449463

Improved performance of ELMy H-modes at high density by plasma shaping in JET
journal, August 2002

Saibene, G.; Sartori, R.; Loarte, A.
Plasma Physics and Controlled Fusion, Vol. 44, Issue 9
DOI: 10.1088/0741-3335/44/9/301

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

Loarte, A.; Hughes, J. W.; Reinke, M. L.
Physics of Plasmas, Vol. 18, Issue 5
DOI: 10.1063/1.3567547

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

Snyder, P. B.; Osborne, T. H.; Burrell, K. H.
Physics of Plasmas, Vol. 19, Issue 5
DOI: 10.1063/1.3699623

Numerical studies of edge localized instabilities in tokamaks
journal, April 2002

Wilson, H. R.; Snyder, P. B.; Huysmans, G. T. A.
Physics of Plasmas, Vol. 9, Issue 4
DOI: 10.1063/1.1459058

Pedestal study across a deuterium fuelling scan for high δ ELMy H-mode plasmas on JET with the carbon wall
journal, July 2013

Leyland, M. J.; Beurskens, M. N. A.; Frassinetti, L.
Nuclear Fusion, Vol. 53, Issue 8
DOI: 10.1088/0029-5515/53/8/083028

Pedestal structure and stability in H-mode and I-mode: a comparative study on Alcator C-Mod
journal, March 2013

Hughes, J. W.; Snyder, P. B.; Walk, J. R.
Nuclear Fusion, Vol. 53, Issue 4
DOI: 10.1088/0029-5515/53/4/043016

Edge pedestal control in quiescent H-mode discharges in DIII-D using co-plus counter-neutral beam injection
journal, July 2009

Burrell, K. H.; Osborne, T. H.; Snyder, P. B.
Nuclear Fusion, Vol. 49, Issue 8
DOI: 10.1088/0029-5515/49/8/085024

Development and validation of a predictive model for the pedestal height
journal, May 2009

Snyder, P. B.; Groebner, R. J.; Leonard, A. W.
Physics of Plasmas, Vol. 16, Issue 5
DOI: 10.1063/1.3122146

The H-mode pedestal structure and its role on confinement in JET with a carbon and metal wall
journal, December 2014

Leyland, M. J.; Beurskens, M. N. A.; Frassinetti, L.
Nuclear Fusion, Vol. 55, Issue 1
DOI: 10.1088/0029-5515/55/1/013019

Effects of a sheared toroidal rotation on the stability boundary of the MHD modes in the tokamak edge pedestal
journal, May 2009

Aiba, N.; Tokuda, S.; Furukawa, M.
Nuclear Fusion, Vol. 49, Issue 6
DOI: 10.1088/0029-5515/49/6/065015

Full linearized Fokker–Planck collisions in neoclassical transport simulations
journal, December 2011

Belli, E. A.; Candy, J.
Plasma Physics and Controlled Fusion, Vol. 54, Issue 1
DOI: 10.1088/0741-3335/54/1/015015

MHD stability analysis of small ELM regimes in JET
journal, December 2008

Saarelma, S.; Alfier, A.; Beurskens, M. N. A.
Plasma Physics and Controlled Fusion, Vol. 51, Issue 3
DOI: 10.1088/0741-3335/51/3/035001

Edge stability of stationary ELM-suppressed regimes on DIII-D
journal, July 2008

Osborne, T. H.; Snyder, P. B.; Burrell, K. H.
Journal of Physics: Conference Series, Vol. 123
DOI: 10.1088/1742-6596/123/1/012014

Characterization of peeling–ballooning stability limits on the pedestal
journal, April 2004

Snyder, P. B.; Wilson, H. R.; Osborne, T. H.
Plasma Physics and Controlled Fusion, Vol. 46, Issue 5A
DOI: 10.1088/0741-3335/46/5A/014

ELMs: MHD instabilities at the transport barrier
journal, November 2005

Huysmans, G. T. A.
Plasma Physics and Controlled Fusion, Vol. 47, Issue 12B
DOI: 10.1088/0741-3335/47/12B/S13

Access to a New Plasma Edge State with High Density and Pressures using the Quiescent $H$ Mode
journal, September 2014

Solomon, W. M.; Snyder, P. B.; Burrell, K. H.
Physical Review Letters, Vol. 113, Issue 13
DOI: 10.1103/PhysRevLett.113.135001

Works referencing / citing this record:

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

Lyons, B. C.; Paz-Soldan, C.; Meneghini, O.
Physics of Plasmas, Vol. 25, Issue 5
DOI: 10.1063/1.5025838

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

Abstract

Citation Formats

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

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Pedestal stability comparison and ITER pedestal prediction journal, July 2009

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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

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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

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H-mode pedestal scaling in DIII-D, ASDEX Upgrade, and JET
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A first-principles predictive model of the pedestal height and width: development, testing and ITER optimization with the EPED model
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Limits to the H-mode pedestal pressure gradient in DIII-D
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Impact of T _e and n _e on edge current density profiles in ELM mitigated regimes on ASDEX Upgrade
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Pedestal stability comparison and ITER pedestal prediction
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Stability and dynamics of the edge pedestal in the low collisionality regime: physics mechanisms for steady-state ELM-free operation
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Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes
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