Investigation of the role of pedestal pressure and collisionality on type-I ELM divertor heat loads in DIII-D

Knolker, M.; Bortolon, A.; Canal, G. P.; Evans, T. E.; Zohm, H.; Abrams, T.; Buttery, R. J.; Davis, E. M.; Groebner, R. J.; Hollmann, E.; Fenstermacher, M. E.; Lasnier, C.; Leonard, A. W.; Moyer, R. A.; Nazikian, R.; Osborne, T. H.; Paz-Soldan, C.; Sieglin, B.

doi:10.1088/1741-4326/aace92

Investigation of the role of pedestal pressure and collisionality on type-I ELM divertor heat loads in DIII-D

Journal Article · Wed Jul 11 00:00:00 EDT 2018 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/aace92· OSTI ID:1460098

^[1]; ^[2]; Canal, G. P. ^[3]; Evans, T. E. ^[3]; Zohm, H. ^[4]; Abrams, T. ^[3]; Buttery, R. J. ^[3]; Davis, E. M. ^[5]; Groebner, R. J. ^[3]; Hollmann, E. ^[6]; Fenstermacher, M. E. ^[7]; Lasnier, C. ^[7]; ^[3]; Moyer, R. A. ^[6]; Nazikian, R. ^[2]; Osborne, T. H. ^[3]; ^[3]; Sieglin, B. ^[4]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
General Atomics, San Diego, CA (United States)
Max Planck Inst. for Plasma Physics, Garching (Germany)
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Univ. of California, San Diego, CA (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Here, a non-dimensional collisionality scan conducted on DIII-D confirms a model for ELM energy densities recently put forward by Eich [1], but also reveals key effects that may explain the large scatter typically observed about the scaling. Electron Cyclotron Heating (ECH) close to the plasma edge was used to raise electron temperatures at the pedestal top and lower collisionality to ITER level, while the power of Neutral Beam Injection (NBI) was decreased during discharges to operate closer to the L-H transition threshold. The scan reveals no explicit pedestal pressure dependence of the ELM energy densities. While collisionality does not play a decisive role, the ratio of heating power to the power over the L-H-threshold is identified as parameter determining the agreement with the model, with discharges marginally above the threshold showing the largest scatter in the database and exceeding the predicted ELM energy up to twofold. Operation close to the L-H-threshold is accompanied by low ELM frequency and large 2 ELM heat loads. Using linear stability calculations, ELM energy densities are shown to be inversely proportional to the most unstable linear mode number before the ELM crash. There are indications that the scatter in the data when compared with the Eich model prediction is caused by including only a limited set out of all quantities in the model that are considered by linear stability analysis. While further ELM studies near the LH threshold are of great priority, the overall agreement of DIII-D with the Eich model recommends its use in extrapolations towards ITER.

View Accepted Manuscript (DOE)

Research Organization:: General Atomics, San Diego, CA (United States). DIII-D National Fusion Facility (DIII-D); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division

Grant/Contract Number:: FC02-04ER54698; FG02-07ER54917; FG02-05ER54809

OSTI ID:: 1460098

Alternate ID(s):: OSTI ID: 1542716
OSTI ID: 22929482

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 9 Vol. 58; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (42)

Measurements of non-axisymmetric effects in the DIII-D divertor Evans, T. E.; Lasnier, C. J.; Hill, D. N. Journal of Nuclear Materials, Vol. 220-222 https://doi.org/10.1016/0022-3115(94)00419-6	journal	April 1995
An Empirical Approach to Tokamak Transport Hawryluk, R. J. Physics of Plasmas Close to Thermonuclear Conditions, p. 19-46 https://doi.org/10.1016/B978-1-4832-8385-2.50009-1	book	January 1979
The tokamak Monte Carlo fast ion module NUBEAM in the National Transport Code Collaboration library Pankin, Alexei; McCune, Douglas; Andre, Robert Computer Physics Communications, Vol. 159, Issue 3 https://doi.org/10.1016/j.cpc.2003.11.002	journal	June 2004
ELM flushing and impurity transport in the H-mode edge barrier in ASDEX Upgrade Pütterich, T.; Dux, R.; Janzer, M. A. Journal of Nuclear Materials, Vol. 415, Issue 1 https://doi.org/10.1016/j.jnucmat.2010.09.052	journal	August 2011
Physics basis and design of the ITER plasma-facing components Pitts, R. A.; Carpentier, S.; Escourbiac, F. Journal of Nuclear Materials, Vol. 415, Issue 1 https://doi.org/10.1016/j.jnucmat.2011.01.114	journal	August 2011
Ion orbit modelling of ELM heat loads on ITER divertor vertical targets Gunn, J. P.; Carpentier-Chouchana, S.; Dejarnac, R. Nuclear Materials and Energy, Vol. 12 https://doi.org/10.1016/j.nme.2016.10.005	journal	August 2017
ELM divertor peak energy fluence scaling to ITER with data from JET, MAST and ASDEX upgrade Eich, T.; Sieglin, B.; Thornton, A. J. Nuclear Materials and Energy, Vol. 12 https://doi.org/10.1016/j.nme.2017.04.014	journal	August 2017
Infrared thermography of the DIII‐D divertor targets Hill, D. N.; Ellis, R.; Ferguson, W. Review of Scientific Instruments, Vol. 59, Issue 8 https://doi.org/10.1063/1.1140040	journal	August 1988
Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes Snyder, P. B.; Wilson, H. R.; Ferron, J. R. Physics of Plasmas, Vol. 9, Issue 5 https://doi.org/10.1063/1.1449463	journal	May 2002
Soft x-ray array system with variable filters for the DIII-D tokamak Hollmann, E. M.; Chousal, L.; Fisher, R. K. Review of Scientific Instruments, Vol. 82, Issue 11 https://doi.org/10.1063/1.3660816	journal	November 2011
Reactor-relevant quiescent H-mode operation using torque from non-axisymmetric, non-resonant magnetic fields Burrell, K. H.; Garofalo, A. M.; Solomon, W. M. Physics of Plasmas, Vol. 19, Issue 5 https://doi.org/10.1063/1.3695119	journal	May 2012
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 Snyder, P. B.; Osborne, T. H.; Burrell, K. H. Physics of Plasmas, Vol. 19, Issue 5 https://doi.org/10.1063/1.3699623	journal	May 2012
Edge-localized-modes in tokamaks Leonard, A. W. Physics of Plasmas, Vol. 21, Issue 9 https://doi.org/10.1063/1.4894742	journal	September 2014
Nondimensional transport scaling in DIII‐D: Bohm versus gyro‐Bohm resolved Petty, C. C.; Luce, T. C.; Burrell, K. H. Physics of Plasmas, Vol. 2, Issue 6 https://doi.org/10.1063/1.871259	journal	June 1995
Noncircular, finite aspect ratio, local equilibrium model Miller, R. L.; Chu, M. S.; Greene, J. M. Physics of Plasmas, Vol. 5, Issue 4 https://doi.org/10.1063/1.872666	journal	April 1998
Neoclassical conductivity and bootstrap current formulas for general axisymmetric equilibria and arbitrary collisionality regime Sauter, O.; Angioni, C.; Lin-Liu, Y. R. Physics of Plasmas, Vol. 6, Issue 7 https://doi.org/10.1063/1.873240	journal	July 1999
Reconstruction of current profile parameters and plasma shapes in tokamaks Lao, L. L.; St. John, H.; Stambaugh, R. D. Nuclear Fusion, Vol. 25, Issue 11 https://doi.org/10.1088/0029-5515/25/11/007	journal	November 1985
Progress in quantifying the edge physics of the H mode regime in DIII-D Groebner, R. J.; Baker, D. R.; Burrell, K. H. Nuclear Fusion, Vol. 41, Issue 12 https://doi.org/10.1088/0029-5515/41/12/306	journal	December 2001
Scaling laws for edge plasma parameters in ITER from two-dimensional edge modelling Kukushkin, A. S.; Pacher, H. D.; Pacher, G. W. Nuclear Fusion, Vol. 43, Issue 8 https://doi.org/10.1088/0029-5515/43/8/312	journal	August 2003
ELM pace making and mitigation by pellet injection in ASDEX Upgrade Lang, P. T.; Conway, G. D.; Eich, T. Nuclear Fusion, Vol. 44, Issue 5 https://doi.org/10.1088/0029-5515/44/5/010	journal	April 2004
ELM transport in the JET scrape-off layer Pitts, R. A.; Andrew, P.; Arnoux, G. Nuclear Fusion, Vol. 47, Issue 11 https://doi.org/10.1088/0029-5515/47/11/005	journal	October 2007
Chapter 4: Power and particle control Loarte, A.; Lipschultz, B.; Kukushkin, A. S. Nuclear Fusion, Vol. 47, Issue 6 https://doi.org/10.1088/0029-5515/47/6/S04	journal	June 2007
Integrated simulation of ELM energy loss and cycle in improved H-mode plasmas Hayashi, N.; Takizuka, T.; Aiba, N. Nuclear Fusion, Vol. 49, Issue 9 https://doi.org/10.1088/0029-5515/49/9/095015	journal	August 2009
A first-principles predictive model of the pedestal height and width: development, testing and ITER optimization with the EPED model Snyder, P. B.; Groebner, R. J.; Hughes, J. W. Nuclear Fusion, Vol. 51, Issue 10 https://doi.org/10.1088/0029-5515/51/10/103016	journal	August 2011
Performance of different tungsten grades under transient thermal loads Linke, J.; Loewenhoff, T.; Massaut, V. Nuclear Fusion, Vol. 51, Issue 7 https://doi.org/10.1088/0029-5515/51/7/073017	journal	June 2011
Scaling radiative divertor solutions to high power in DIII-D Leonard, A. W.; Mahdavi, M. A.; Lasnier, C. J. Nuclear Fusion, Vol. 52, Issue 6 https://doi.org/10.1088/0029-5515/52/6/063015	journal	April 2012
Integrated modeling applications for tokamak experiments with OMFIT Meneghini, O.; Smith, S. P.; Lao, L. L. Nuclear Fusion, Vol. 55, Issue 8 https://doi.org/10.1088/0029-5515/55/8/083008	journal	July 2015
High frequency pacing of edge localized modes by injection of lithium granules in DIII-D H-mode discharges Bortolon, A.; Maingi, R.; Mansfield, D. K. Nuclear Fusion, Vol. 56, Issue 5 https://doi.org/10.1088/0029-5515/56/5/056008	journal	April 2016
Evolution of tungsten degradation under combined high cycle edge-localized mode and steady-state heat loads Loewenhoff, Th; Bürger, A.; Linke, J. Physica Scripta, Vol. T145 https://doi.org/10.1088/0031-8949/2011/T145/014057	journal	December 2011
Optimized profiles for improved confinement and stability in the DIII-D tokamak Taylor, T. S.; John, H. St; Turnbull, A. D. Plasma Physics and Controlled Fusion, Vol. 36, Issue 12B https://doi.org/10.1088/0741-3335/36/12B/019	journal	December 1994
Energy flux to the ASDEX-Upgrade diverter plates determined by thermography and calorimetry Herrmann, A.; Junker, W.; Gunther, K. Plasma Physics and Controlled Fusion, Vol. 37, Issue 1 https://doi.org/10.1088/0741-3335/37/1/002	journal	January 1995
Edge localized modes (ELMs) Zohm, H. Plasma Physics and Controlled Fusion, Vol. 38, Issue 2 https://doi.org/10.1088/0741-3335/38/2/001	journal	February 1996
Disruption heat loads on the JET MkIIGB divertor Riccardo, V.; Andrew, P.; Ingesson, L. C. Plasma Physics and Controlled Fusion, Vol. 44, Issue 6 https://doi.org/10.1088/0741-3335/44/6/319	journal	May 2002
Lithium divertor concept and results of supporting experiments Evtikhin, V. A.; Lyublinski, I. E.; Vertkov, A. V. Plasma Physics and Controlled Fusion, Vol. 44, Issue 6 https://doi.org/10.1088/0741-3335/44/6/322	journal	May 2002
Characteristics of type I ELM energy and particle losses in existing devices and their extrapolation to ITER Loarte, A.; Saibene, G.; Sartori, R. Plasma Physics and Controlled Fusion, Vol. 45, Issue 9 https://doi.org/10.1088/0741-3335/45/9/302	journal	August 2003
Characterization of peeling–ballooning stability limits on the pedestal Snyder, P. B.; Wilson, H. R.; Osborne, T. H. Plasma Physics and Controlled Fusion, Vol. 46, Issue 5A https://doi.org/10.1088/0741-3335/46/5A/014	journal	April 2004
ELM resolved energy distribution studies in the JET MKII Gas-Box divertor using infra-red thermography Eich, T.; Andrew, P.; Herrmann, A. Plasma Physics and Controlled Fusion, Vol. 49, Issue 5 https://doi.org/10.1088/0741-3335/49/5/002	journal	March 2007
Power requirement for accessing the H-mode in ITER Martin, Y. R.; Takizuka, T.; Group, the ITPA CDBM H-mode Threshold Data Journal of Physics: Conference Series, Vol. 123 https://doi.org/10.1088/1742-6596/123/1/012033	journal	July 2008
First Observation of Edge Localized Modes Mitigation with Resonant and Nonresonant Magnetic Perturbations in ASDEX Upgrade Suttrop, W.; Eich, T.; Fuchs, J. C. Physical Review Letters, Vol. 106, Issue 22 https://doi.org/10.1103/PhysRevLett.106.225004	journal	June 2011
Inter-ELM Power Decay Length for JET and ASDEX Upgrade: Measurement and Comparison with Heuristic Drift-Based Model Eich, T.; Sieglin, B.; Scarabosio, A. Physical Review Letters, Vol. 107, Issue 21 https://doi.org/10.1103/PhysRevLett.107.215001	journal	November 2011
Suppression of Large Edge-Localized Modes in High-Confinement DIII-D Plasmas with a Stochastic Magnetic Boundary Evans, T. E.; Moyer, R. A.; Thomas, P. R. Physical Review Letters, Vol. 92, Issue 23 https://doi.org/10.1103/PhysRevLett.92.235003	journal	June 2004
Active Control of Type-I Edge-Localized Modes with n = 1 Perturbation Fields in the JET Tokamak Liang, Y.; Koslowski, H. R.; Thomas, P. R. Physical Review Letters, Vol. 98, Issue 26 https://doi.org/10.1103/PhysRevLett.98.265004	journal	June 2007

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