Effects of divertor geometry on H-mode pedestal structure in attached and detached plasmas in the DIII-D tokamak [Effects of divertor geometry on H-mode pedestal structure near divertor detachment in the DIII-D tokamak]

Wang, H. Q.; Guo, H. Y.; Leonard, A. W.; Moser, A. L.; Osborne, T. H.; Snyder, P. B.; Belli, E.; Groebner, R. J.; Thomas, D. M.; Watkins, J. G.; Yan, Z.

doi:10.1088/1741-4326/aacbde

Title: Effects of divertor geometry on H-mode pedestal structure in attached and detached plasmas in the DIII-D tokamak [Effects of divertor geometry on H-mode pedestal structure near divertor detachment in the DIII-D tokamak]

Journal Article · Thu Jul 05 00:00:00 EDT 2018 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/aacbde· OSTI ID:1461182

Wang, H. Q. ^[1]; Guo, H. Y. ^[2];

^[2]; Moser, A. L. ^[2]; Osborne, T. H. ^[2]; Snyder, P. B. ^[2]; Belli, E. ^[2]; Groebner, R. J. ^[2]; Thomas, D. M. ^[2]; Watkins, J. G. ^[3]; Yan, Z. ^[4]

Oak Ridge Associated Univ., Oak Ridge, TN (United States)
General Atomics, San Diego, CA (United States)
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Univ. of Wisconsin-Madison, Madison, WI (United States)

Dedicated experiments have been performed in the DIII-D tokamak to assess the influence of divertor geometry on the H-mode pedestal structure. It has been found that in both attached and detached plasmas, compared to the open divertor, the more closed divertor traps more neutrals in the divertor region, leading to lower pedestal fueling and thus results in lower density and higher temperature at the pedestal top. In addition, approaching divertor detachment by increasing the gas-puffing rate, for different divertor geometries, the pedestal width exhibits different trends. In the attached plasma, the pedestal width agrees well with the theoretical and empirical pedestal-poloidal-beta scaling. However, during divertor detachment, in the open divertor the pedestal width is significantly reduced. In contrast, for detached plasmas with the more closed divertor, the pedestal is significantly wider, by up to 50% compared to the theoretical scaling. Moreover, near divertor detachment, the open diverted plasma exhibits a more aligned density and temperature pedestal profile, while in the closed divertor the detachment results in a relative shift (up to 50% of the pedestal width) between the density and temperature pedestal profiles. Such changes in the pedestal structure, coupled with reduced pedestal fueling, allow for the achievement of divertor detachment while retaining high pedestal performance with the more closed divertor.

View Accepted Manuscript (DOE)

Cite

Export

Save

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

Sponsoring Organization:: USDOE Office of Nuclear Energy (NE)

Contributing Organization:: The DIII-D group

Grant/Contract Number:: FC02-04ER54698

OSTI ID:: 1461182

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

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

Citation Metrics:

Cited by: 26 works

Citation information provided by
Web of Science

References (46)

Effect of the relative shift between the electron density and temperature pedestal position on the pedestal stability in JET-ILW and comparison with JET-C Stefanikova, E.; Frassinetti, L.; Saarelma, S. Nuclear Fusion, Vol. 58, Issue 5 https://doi.org/10.1088/1741-4326/aab216	journal	March 2018
H-mode pedestal scaling in DIII-D, ASDEX Upgrade, and JET Beurskens, M. N. A.; Osborne, T. H.; Schneider, P. A. Physics of Plasmas, Vol. 18, Issue 5 https://doi.org/10.1063/1.3593008	journal	May 2011
Improved confinement in JET high β plasmas with an ITER-like wall Challis, C. D.; Garcia, J.; Beurskens, M. Nuclear Fusion, Vol. 55, Issue 5 https://doi.org/10.1088/0029-5515/55/5/053031	journal	April 2015
Separation of β̄ _p and ℓ _i in tokamaks of non-circular cross-section Lao, L. L.; John, H. St.; Stambaugh, R. D. Nuclear Fusion, Vol. 25, Issue 10 https://doi.org/10.1088/0029-5515/25/10/004	journal	October 1985
ELMs and constraints on the H-mode pedestal: peeling–ballooning stability calculation and comparison with experiment Snyder, P. B.; Wilson, H. R.; Ferron, J. R. Nuclear Fusion, Vol. 44, Issue 2 https://doi.org/10.1088/0029-5515/44/2/014	journal	January 2004
Effects of divertor geometry on tokamak plasmas Loarte, Alberto Plasma Physics and Controlled Fusion, Vol. 43, Issue 6 https://doi.org/10.1088/0741-3335/43/6/201	journal	May 2001
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
Linear gyrokinetic simulations of microinstabilities within the pedestal region of H-mode NSTX discharges in a highly shaped geometry Coury, M.; Guttenfelder, W.; Mikkelsen, D. R. Physics of Plasmas, Vol. 23, Issue 6 https://doi.org/10.1063/1.4954911	journal	June 2016
Limits to the H-mode pedestal pressure gradient in DIII-D Groebner, R. J.; Snyder, P. B.; Osborne, T. H. Nuclear Fusion, Vol. 50, Issue 6 https://doi.org/10.1088/0029-5515/50/6/064002	journal	May 2010
Plasma detachment in divertor tokamaks Leonard, A. W. Plasma Physics and Controlled Fusion, Vol. 60, Issue 4 https://doi.org/10.1088/1361-6587/aaa7a9	journal	February 2018
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
Pedestal stability comparison and ITER pedestal prediction Snyder, P. B.; Aiba, N.; Beurskens, M. Nuclear Fusion, Vol. 49, Issue 8 https://doi.org/10.1088/0029-5515/49/8/085035	journal	July 2009
A new experimental classification of divertor detachment in ASDEX Upgrade Potzel, S.; Wischmeier, M.; Bernert, M. Nuclear Fusion, Vol. 54, Issue 1 https://doi.org/10.1088/0029-5515/54/1/013001	journal	November 2013
H-mode pedestal characteristics, ELMs, and energy confinement in ITER shape discharges on DIII-D Osborne, T. H.; Groebner, R. J.; Lao, L. L. Plasma Physics and Controlled Fusion, Vol. 40, Issue 5 https://doi.org/10.1088/0741-3335/40/5/054	journal	May 1998
Studies of high-δ (baffled) and low-δ (open) pumped divertor operation on DIII-D Allen, S. L.; Fenstermacher, M. E.; Greenfield, C. M. Journal of Nuclear Materials, Vol. 266-269 https://doi.org/10.1016/s0022-3115(98)00523-6	journal	March 1999
Compatibility of separatrix density scaling for divertor detachment with H-mode pedestal operation in DIII-D Leonard, A. W.; McLean, A. G.; Makowski, M. A. Nuclear Fusion, Vol. 57, Issue 8 https://doi.org/10.1088/1741-4326/aa778c	journal	July 2017
Critical gradient formula for toroidal electron temperature gradient modes Jenko, F.; Dorland, W.; Hammett, G. W. Physics of Plasmas, Vol. 8, Issue 9 https://doi.org/10.1063/1.1391261	journal	September 2001
Characterization of the separatrix plasma parameters in DIII-D Porter, G. D.; Moller, J.; Brown, M. Physics of Plasmas, Vol. 5, Issue 5 https://doi.org/10.1063/1.872830	journal	May 1998
Structure, stability and ELM dynamics of the H-mode pedestal in DIII-D Fenstermacher, M. E.; Osborne, T. H.; Leonard, A. W. Nuclear Fusion, Vol. 45, Issue 12 https://doi.org/10.1088/0029-5515/45/12/004	journal	November 2005
Assessment of the poloidal distribution of core plasma fueling and impurity sources in DIII-D Groth, M.; Owen, L. W.; Porter, G. D. Journal of Nuclear Materials, Vol. 337-339 https://doi.org/10.1016/j.jnucmat.2004.09.068	journal	March 2005
Scaling and profiles of heat flux during partial detachment in DIII-D Lasnier, C. J.; Hill, D. N.; Allen, S. L. Journal of Nuclear Materials, Vol. 266-269 https://doi.org/10.1016/s0022-3115(98)00544-3	journal	March 1999
Contrasting H-mode behaviour with deuterium fuelling and nitrogen seeding in the all-carbon and metallic versions of JET Maddison, G. P.; Giroud, C.; Alper, B. Nuclear Fusion, Vol. 54, Issue 7 https://doi.org/10.1088/0029-5515/54/7/073016	journal	May 2014
Magnetohydrodynamic stability of tokamak edge plasmas Connor, J. W.; Hastie, R. J.; Wilson, H. R. Physics of Plasmas, Vol. 5, Issue 7 https://doi.org/10.1063/1.872956	journal	July 1998
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
Poloidal asymmetries in the edge density profiles on ASDEX Upgrade Guimarais, L.; Potzel, S.; Silva, C. Nuclear Fusion, Vol. 58, Issue 2 https://doi.org/10.1088/1741-4326/aa98e8	journal	December 2017
SOL effects on the pedestal structure in DIII-D discharges Sontag, A. C.; Chen, X.; Canik, J. Nuclear Fusion, Vol. 57, Issue 7 https://doi.org/10.1088/1741-4326/aa6cb6	journal	May 2017
Magneto-hydrodynamic stability of the H-mode transport barrier as a model for edge localized modes: an overview Wilson, H. R.; Cowley, S. C.; Kirk, A. Plasma Physics and Controlled Fusion, Vol. 48, Issue 5A https://doi.org/10.1088/0741-3335/48/5a/s06	journal	April 2006
Chapter 2: Plasma confinement and transport Transport, ITER Physics Expert Group on Confin; Database, ITER Physics Expert Group on Confin; Editors, ITER Physics Basis Nuclear Fusion, Vol. 39, Issue 12 https://doi.org/10.1088/0029-5515/39/12/302	journal	December 1999
Comparison of H-mode barrier width with a model of neutral penetration length Groebner, R. J.; Mahdavi, M. A.; Leonard, A. W. Nuclear Fusion, Vol. 44, Issue 1 https://doi.org/10.1088/0029-5515/44/1/022	journal	December 2003
Initial performance results of the DIII-D Divertor 2000 Mahdavi, M. A.; Wade, M. R.; Watkins, J. G. Journal of Nuclear Materials, Vol. 290-293 https://doi.org/10.1016/s0022-3115(00)00500-6	journal	March 2001
Ideal magnetohydrodynamic stability of the tokamak high-confinement-mode edge region Wilson, H. R.; Connor, J. W.; Field, A. R. Physics of Plasmas, Vol. 6, Issue 5 https://doi.org/10.1063/1.873492	journal	May 1999
Physics of pedestal density profile formation and its impact on H-mode density limit in burning plasmas Mahdavi, M. A.; Maingi, R.; Groebner, R. J. Physics of Plasmas, Vol. 10, Issue 10 https://doi.org/10.1063/1.1605101	journal	October 2003
Edge profile stiffness and insensitivity of the density pedestal to neutral fuelling in Alcator C-Mod edge transport barriers Hughes, J. W.; LaBombard, B.; Terry, J. Nuclear Fusion, Vol. 47, Issue 8 https://doi.org/10.1088/0029-5515/47/8/041	journal	August 2007
Development and validation of a predictive model for the pedestal height Snyder, P. B.; Groebner, R. J.; Leonard, A. W. Physics of Plasmas, Vol. 16, Issue 5 https://doi.org/10.1063/1.3122146	journal	May 2009
Compatibility of detached divertor operation with robust edge pedestal performance Leonard, A. W.; Makowski, M. A.; McLean, A. G. Journal of Nuclear Materials, Vol. 463 https://doi.org/10.1016/j.jnucmat.2014.11.007	journal	August 2015
Comparison of theoretical and experimental heat diffusivities in the DIII-D edge plasma Stacey, W. M. Physics of Plasmas, Vol. 15, Issue 5 https://doi.org/10.1063/1.2920766	journal	May 2008
Analysis of temperature and density pedestal gradients in AUG, DIII-D and JET Schneider, P. A.; Wolfrum, E.; Groebner, R. J. Nuclear Fusion, Vol. 53, Issue 7 https://doi.org/10.1088/0029-5515/53/7/073039	journal	June 2013
Enhanced H-mode pedestals with lithium injection in DIII-D Osborne, T. H.; Jackson, G. L.; Yan, Z. Nuclear Fusion, Vol. 55, Issue 6 https://doi.org/10.1088/0029-5515/55/6/063018	journal	May 2015
Chapter 2: Plasma confinement and transport 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 https://doi.org/10.1088/0029-5515/47/6/S02	journal	June 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
Radiative divertor and scrape-off layer experiments in open and baffled divertors on DIII-D Allen, S. L.; Brooks, N. H.; Bastasz, R. Nuclear Fusion, Vol. 39, Issue 11Y https://doi.org/10.1088/0029-5515/39/11Y/348	journal	November 1999
Experiments and computational modeling focused on divertor and SOL optimization for advanced tokamak operation on DIII-D Allen, S. L.; Boedo, J. A.; Bozek, A. S. Journal of Nuclear Materials, Vol. 290-293 https://doi.org/10.1016/S0022-3115(00)00501-8	journal	March 2001
Performance of high triangularity plasmas as the volume of the secondary divertor is varied in DIII-D Fenstermacher, M. E.; Osborne, T. H.; Petrie, T. W. Journal of Nuclear Materials, Vol. 290-293 https://doi.org/10.1016/S0022-3115(00)00526-2	journal	March 2001
Density Gradient Stabilization of Electron Temperature Gradient Driven Turbulence in a Spherical Tokamak Ren, Y.; Kaye, S. M.; Mazzucato, E. Physical Review Letters, Vol. 106, Issue 16 https://doi.org/10.1103/PhysRevLett.106.165005	journal	April 2011
Short-Scale Turbulent Fluctuations Driven by the Electron-Temperature Gradient in the National Spherical Torus Experiment Mazzucato, E.; Smith, D. R.; Bell, R. E. Physical Review Letters, Vol. 101, Issue 7 https://doi.org/10.1103/PhysRevLett.101.075001	journal	August 2008
Improved Confinement in JET High {beta} Plasmas with an ITER-Like Wall Challis, C. D.; Garcia, J.; Beurskens, M. arXiv https://doi.org/10.48550/arxiv.1501.03929	text	January 2015

Similar Records

Study on divertor detachment and pedestal characteristics in the DIII-D upper closed divertor

Journal Article · Tue Feb 14 00:00:00 EST 2023 · Nuclear Fusion · OSTI ID:1461182

Wang, H. Q.; Thomas, D. M.; Leonard, A. W.; +12 more

SOL effects on the pedestal structure in DIII-D discharges

Journal Article · Wed May 24 00:00:00 EDT 2017 · Nuclear Fusion · OSTI ID:1461182

Sontag, Aaron C.; Chen, Xi; Canik, John; +6 more

Separating divertor closure effects on divertor detachment and pedestal shape in DIII-D

Journal Article · Thu Mar 12 00:00:00 EDT 2020 · Physics of Plasmas · OSTI ID:1461182

Moser, A. L.; Casali, L.; Covele, B. M.; +5 more

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
H-mode pedestal
divertor geometry
divertor detachment

Title: Effects of divertor geometry on H-mode pedestal structure in attached and detached plasmas in the DIII-D tokamak [Effects of divertor geometry on H-mode pedestal structure near divertor detachment in the DIII-D tokamak]

Citation Formats

References (46)

Similar Records

Related Subjects