Setting the H-mode pedestal structure: variations of particle source location using gas puff and pellet fueling
Abstract
Experiments in DIII-D show that a particle source location inside the top of the H-mode pedestal (pellets) maintains a higher pedestal pressure than an edge source (gas fueling) through a widening of the electron temperature pedestal with reduction of the temperature gradient. The effect of these two fueling schemes on the H-mode pedestal structure was examined in DIII-D by comparing controlled pellet-fueled and gas-fueled discharges across a fueling scan up to 40 torr 1 s–1. High resolution electron profiles reveal that gas fueling lowers the pedestal pressure as the density profile shifts radially outwards and the separatrix density increases, while pellet fueling maintains a constant pedestal pressure. The neutral source locations from pellets and gas are determined with the PELLET and UEDGE codes, respectively, and quantify the particle source localization. Pellets provide significant ionization inside the pedestal top while gas puffing localizes ionization in the scrape-off-layer and pedestal foot, broadly consistent with the density profile structure influenced by the source. ELMs are observed to increase in frequency and reduce impurity content as fueling is increased. Stability analysis with ELITE shows that both conditions are near the type-I ELM corner of the peeling–ballooning stability diagram, which is altered significantly by themore »
- Authors:
-
[1];
[1];
[1];
[3];
[2];
[4];
[2];
[5];
[5];
[3]
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- General Atomics, San Diego, CA (United States)
- Princeton Univ., NJ (United States)
- ORNL
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Publication Date:
- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Contributing Org.:
- DIII-D Team
- OSTI Identifier:
- 1657913
- Alternate Identifier(s):
- OSTI ID: 1577354; OSTI ID: 1668769
- Report Number(s):
- 2020_180
Journal ID: ISSN 0029-5515; TRN: US2203306
- Grant/Contract Number:
- AC05-00OR22725; AC02-09CH11466; SC0015480; SC0015878; FC02-04ER54698
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 60; Journal Issue: 4; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma; tokamak; pellet; gas puff; pedestal; gas puff
Citation Formats
Nelson, Andrew Oakleigh, Laggner, Florian M., Groebner, Richard J., Grierson, Brian A., Izacard, Olivier, Eldon, David, Shafer, Morgan W., Leonard, Anthony W., Shiraki, Daisuke, Sontag, Aaron C., and Kolemen, Egemen. Setting the H-mode pedestal structure: variations of particle source location using gas puff and pellet fueling. United States: N. p., 2020.
Web. doi:10.1088/1741-4326/ab5e65.
Nelson, Andrew Oakleigh, Laggner, Florian M., Groebner, Richard J., Grierson, Brian A., Izacard, Olivier, Eldon, David, Shafer, Morgan W., Leonard, Anthony W., Shiraki, Daisuke, Sontag, Aaron C., & Kolemen, Egemen. Setting the H-mode pedestal structure: variations of particle source location using gas puff and pellet fueling. United States. https://doi.org/10.1088/1741-4326/ab5e65
Nelson, Andrew Oakleigh, Laggner, Florian M., Groebner, Richard J., Grierson, Brian A., Izacard, Olivier, Eldon, David, Shafer, Morgan W., Leonard, Anthony W., Shiraki, Daisuke, Sontag, Aaron C., and Kolemen, Egemen. Fri .
"Setting the H-mode pedestal structure: variations of particle source location using gas puff and pellet fueling". United States. https://doi.org/10.1088/1741-4326/ab5e65. https://www.osti.gov/servlets/purl/1657913.
@article{osti_1657913,
title = {Setting the H-mode pedestal structure: variations of particle source location using gas puff and pellet fueling},
author = {Nelson, Andrew Oakleigh and Laggner, Florian M. and Groebner, Richard J. and Grierson, Brian A. and Izacard, Olivier and Eldon, David and Shafer, Morgan W. and Leonard, Anthony W. and Shiraki, Daisuke and Sontag, Aaron C. and Kolemen, Egemen},
abstractNote = {Experiments in DIII-D show that a particle source location inside the top of the H-mode pedestal (pellets) maintains a higher pedestal pressure than an edge source (gas fueling) through a widening of the electron temperature pedestal with reduction of the temperature gradient. The effect of these two fueling schemes on the H-mode pedestal structure was examined in DIII-D by comparing controlled pellet-fueled and gas-fueled discharges across a fueling scan up to 40 torr 1 s–1. High resolution electron profiles reveal that gas fueling lowers the pedestal pressure as the density profile shifts radially outwards and the separatrix density increases, while pellet fueling maintains a constant pedestal pressure. The neutral source locations from pellets and gas are determined with the PELLET and UEDGE codes, respectively, and quantify the particle source localization. Pellets provide significant ionization inside the pedestal top while gas puffing localizes ionization in the scrape-off-layer and pedestal foot, broadly consistent with the density profile structure influenced by the source. ELMs are observed to increase in frequency and reduce impurity content as fueling is increased. Stability analysis with ELITE shows that both conditions are near the type-I ELM corner of the peeling–ballooning stability diagram, which is altered significantly by the introduction of pellets. Since transport mechanisms are not observed to change substantially with particle source location, wider pedestals allow the pellet-fueled discharges to retain higher pedestal temperatures at similar pedestal densities. EPED1 is tested to capture the pedestal pressure, under-predicting the height with pellets and over-predicting the height with gas by ~15%. Overall, these results have important implications for future reactors where pellet fueling will be the primary particle source due to an opaque scrape-off-layer by showing that the neutral source location plays a role in setting the structure of the H-mode pedestal.},
doi = {10.1088/1741-4326/ab5e65},
journal = {Nuclear Fusion},
number = 4,
volume = 60,
place = {United States},
year = {Fri Feb 21 00:00:00 EST 2020},
month = {Fri Feb 21 00:00:00 EST 2020}
}
Free Publicly Available Full Text
Publisher's Version of Record
Other availability
Search WorldCat to find libraries that may hold this journal
Cited by: 8 works
Citation information provided by
Web of Science
Web of Science
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.
Works referenced in this record:
Parameter dependences of small edge localized modes (ELMs)
journal, September 2018
- Harrer, G. F.; Wolfrum, E.; Dunne, M. G.
- Nuclear Fusion, Vol. 58, Issue 11
Integrated simulations of H-mode operation in ITER including core fuelling, divertor detachment and ELM control
journal, March 2018
- Polevoi, A. R.; Loarte, A.; Dux, R.
- Nuclear Fusion, Vol. 58, Issue 5
Reconstruction of current profile parameters and plasma shapes in tokamaks
journal, November 1985
- Lao, L. L.; St. John, H.; Stambaugh, R. D.
- Nuclear Fusion, Vol. 25, Issue 11
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
Initial results of the high resolution edge Thomson scattering upgrade at DIII-D
journal, October 2012
- Eldon, D.; Bray, B. D.; Deterly, T. M.
- Review of Scientific Instruments, Vol. 83, Issue 10
Improved edge charge exchange recombination spectroscopy in DIII-D
journal, August 2016
- Chrystal, C.; Burrell, K. H.; Grierson, B. A.
- Review of Scientific Instruments, Vol. 87, Issue 11
ELM pace making and mitigation by pellet injection in ASDEX Upgrade
journal, April 2004
- Lang, P. T.; Conway, G. D.; Eich, T.
- Nuclear Fusion, Vol. 44, Issue 5
Pellet fuelling and control of burning plasmas in ITER
journal, May 2007
- Baylor, L. R.; Parks, P. B.; Jernigan, T. C.
- Nuclear Fusion, Vol. 47, Issue 5
Analysis of fuelling requirements in ITER H-modes with SOLPS-EPED1 derived scalings
journal, September 2016
- Polevoi, A. R.; Loarte, A.; Kukushkin, A. S.
- Nuclear Fusion, Vol. 57, Issue 2
Neoclassical conductivity and bootstrap current formulas for general axisymmetric equilibria and arbitrary collisionality regime
journal, July 1999
- Sauter, O.; Angioni, C.; Lin-Liu, Y. R.
- Physics of Plasmas, Vol. 6, Issue 7
Pellet fuelling, ELM pacing and disruption mitigation technology development for ITER
journal, July 2009
- Baylor, L. R.; Combs, S. K.; Foust, C. R.
- Nuclear Fusion, Vol. 49, Issue 8
OMFIT Tokamak Profile Data Fitting and Physics Analysis
journal, January 2018
- Logan, N. C.; Grierson, B. A.; Haskey, S. R.
- Fusion Science and Technology, Vol. 74, Issue 1-2
Neutral and plasma shielding model for pellet ablation
journal, April 1988
- Houlberg, W. A.; Milora, S. L.; Attenberger, S. E.
- Nuclear Fusion, Vol. 28, Issue 4
Structure, stability and ELM dynamics of the H-mode pedestal in DIII-D
journal, November 2005
- Fenstermacher, M. E.; Osborne, T. H.; Leonard, A. W.
- Nuclear Fusion, Vol. 45, Issue 12
Orchestrating TRANSP Simulations for Interpretative and Predictive Tokamak Modeling with OMFIT
journal, February 2018
- Grierson, B. A.; Yuan, X.; Gorelenkova, M.
- Fusion Science and Technology, Vol. 74, Issue 1-2
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
High frequency pacing of edge localized modes by injection of lithium granules in DIII-D H-mode discharges
journal, April 2016
- Bortolon, A.; Maingi, R.; Mansfield, D. K.
- Nuclear Fusion, Vol. 56, Issue 5
Simulations of density profiles, pellet fuelling and density control in ITER
journal, November 2011
- Garzotti, L.; Belo, P.; Corrigan, G.
- Nuclear Fusion, Vol. 52, Issue 1
Screening of a high-density plasma from neutral gas penetration
journal, October 1968
- Lehnert, B.
- Nuclear Fusion, Vol. 8, Issue 3
Chapter 2: Plasma confinement and transport
journal, December 1999
- Transport, ITER Physics Expert Group on Confin; Database, ITER Physics Expert Group on Confin; Editors, ITER Physics Basis
- Nuclear Fusion, Vol. 39, Issue 12
Reduction of Edge-Localized Mode Intensity Using High-Repetition-Rate Pellet Injection in Tokamak -Mode Plasmas
journal, June 2013
- Baylor, L. R.; Commaux, N.; Jernigan, T. C.
- Physical Review Letters, Vol. 110, Issue 24
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
Scaling laws for edge plasma parameters in ITER from two-dimensional edge modelling
journal, August 2003
- Kukushkin, A. S.; Pacher, H. D.; Pacher, G. W.
- Nuclear Fusion, Vol. 43, Issue 8
Particle confinement of pellet-fuelled tokamak plasma
journal, May 2008
- Valovič, M.; Axon, K.; Garzotti, L.
- Nuclear Fusion, Vol. 48, Issue 7
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
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
Advances in measurement and modeling of the high-confinement-mode pedestal on the Alcator C-Mod tokamak
journal, May 2006
- Hughes, J. W.; LaBombard, B.; Mossessian, D. A.
- Physics of Plasmas, Vol. 13, Issue 5
Radiative divertor experiments in DIII-D with D 2 injection
journal, March 1997
- Petrie, T. W.; Hill, D. N.; Allen, S. L.
- Nuclear Fusion, Vol. 37, Issue 3
Chapter 2: Plasma confinement and transport
journal, June 2007
- Physics), E. J. Doyle (Chair Transport; Modelling), W. A. Houlberg (Chair Confinement Da; Edge), Y. Kamada (Chair Pedestal and
- Nuclear Fusion, Vol. 47, Issue 6
Characteristics of ELM activity and fueling efficiency of pellet injection from different locations on DIII-D
journal, March 2001
- Baylor, L. R.; Jernigan, T. C.; Colchin, R. J.
- Journal of Nuclear Materials, Vol. 290-293
Integrated modeling applications for tokamak experiments with OMFIT
journal, July 2015
- Meneghini, O.; Smith, S. P.; Lao, L. L.
- Nuclear Fusion, Vol. 55, Issue 8
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
Effect of transonic flow in the ablation cloud on the lifetime of a solid hydrogen pellet in a plasma
journal, January 1978
- Parks, P. B.; Turnbull, R. J.
- Physics of Fluids, Vol. 21, Issue 10
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
Pedestal characteristics and extended high-$\beta$p ELMy H-mode regime in JT-60U
journal, April 2002
- Kamada, Y.; Takenaga, H.; Isayama, A.
- Plasma Physics and Controlled Fusion, Vol. 44, Issue 5A
H-mode pedestal characteristics, ELMs, and energy confinement in ITER shape discharges on DIII-D
journal, May 1998
- Osborne, T. H.; Groebner, R. J.; Lao, L. L.
- Plasma Physics and Controlled Fusion, Vol. 40, Issue 5
Identifying the location of the OMP separatrix in DIII-D using power accounting
journal, August 2015
- Stangeby, P. C.; Canik, J. M.; Elder, J. D.
- Nuclear Fusion, Vol. 55, Issue 9
Energy Confinement of High-Density Pellet-Fueled Plasmas in the Alcator Tokamak
journal, July 1984
- Greenwald, M.; Gwinn, D.; Milora, S.
- Physical Review Letters, Vol. 53, Issue 4
ELM frequency feedback control on JET
journal, April 2015
- Lennholm, M.; Beaumont, P. S.; Carvalho, I. S.
- Nuclear Fusion, Vol. 55, Issue 6
Progress in quantifying the edge physics of the H mode regime in DIII-D
journal, December 2001
- Groebner, R. J.; Baker, D. R.; Burrell, K. H.
- Nuclear Fusion, Vol. 41, Issue 12
Improved confinement in highly powered high performance scenarios on DIII-D
journal, June 2017
- Petrie, T. W.; Osborne, T.; Fenstermacher, M. E.
- Nuclear Fusion, Vol. 57, Issue 8
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
Design and operation of the multipulse Thomson scattering diagnostic on DIII‐D (invited)
journal, October 1992
- Carlstrom, T. N.; Campbell, G. L.; DeBoo, J. C.
- Review of Scientific Instruments, Vol. 63, Issue 10
Microstability analysis of pellet fuelled discharges in MAST
journal, February 2014
- Garzotti, L.; Figueiredo, J.; Roach, C. M.
- Plasma Physics and Controlled Fusion, Vol. 56, Issue 3
Fueling of QH-mode plasmas on DIII-D with pellets and gas
journal, March 2005
- Baylor, L. R.; Jernigan, T. C.; Burrell, K. H.
- Journal of Nuclear Materials, Vol. 337-339
Physics of pedestal density profile formation and its impact on H-mode density limit in burning plasmas
journal, October 2003
- Mahdavi, M. A.; Maingi, R.; Groebner, R. J.
- Physics of Plasmas, Vol. 10, Issue 10
Edge profile stiffness and insensitivity of the density pedestal to neutral fuelling in Alcator C-Mod edge transport barriers
journal, August 2007
- Hughes, J. W.; LaBombard, B.; Terry, J.
- Nuclear Fusion, Vol. 47, Issue 8
Compatibility of detached divertor operation with robust edge pedestal performance
journal, August 2015
- Leonard, A. W.; Makowski, M. A.; McLean, A. G.
- Journal of Nuclear Materials, Vol. 463
A fully implicit, time dependent 2-D fluid code for modeling tokamak edge plasmas
journal, December 1992
- Rognlien, T. D.; Milovich, J. L.; Rensink, M. E.
- Journal of Nuclear Materials, Vol. 196-198