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26 results on '"V. A. Soukhanovskii"'

1. Overview of physics results from MAST upgrade towards core-pedestal-exhaust integration

Author

J.R. Harrison, A. Aboutaleb, S. Ahmed, M. Aljunid, S.Y. Allan, H. Anand, Y. Andrew, L.C. Appel, A. Ash, J. Ashton, O. Bachmann, M. Barnes, B. Barrett, D. Baver, D. Beckett, J. Bennett, J. Berkery, M. Bernert, W. Boeglin, C. Bowman, J. Bradley, D. Brida, P.K. Browning, D. Brunetti, P. Bryant, J. Bryant, J. Buchanan, N. Bulmer, A. Carruthers, M. Cecconello, Z.P. Chen, J. Clark, C. Cowley, M. Coy, N. Crocker, G. Cunningham, I. Cziegler, T. Da Assuncao, Y. Damizia, P. Davies, I.E. Day, G.L. Derks, S. Dixon, R. Doyle, M. Dreval, M. Dunne, B.P. Duval, T. Eagles, J. Edmond, H. El-Haroun, S.D. Elmore, Y. Enters, M. Faitsch, F. Federici, N. Fedorczak, F. Felici, A.R. Field, M. Fitzgerald, I. Fitzgerald, R. Fitzpatrick, L. Frassinetti, W. Fuller, D. Gahle, J. Galdon-Quiroga, L. Garzotti, S. Gee, T. Gheorghiu, S. Gibson, K.J. Gibson, C. Giroud, D. Greenhouse, V.H. Hall-Chen, C.J. Ham, R. Harrison, S.S. Henderson, C. Hickling, B. Hnat, L. Howlett, J. Hughes, R. Hussain, K. Imada, P. Jacquet, P. Jepson, B. Kandan, I. Katramados, Y.O. Kazakov, D. King, R. King, A. Kirk, M. Knolker, M. Kochan, L. Kogan, B. Kool, M. Kotschenreuther, M. Lees, A.W. Leonard, G. Liddiard, B. Lipschultz, Y.Q. Liu, B.A. Lomanowski, N. Lonigro, J. Lore, J. Lovell, S. Mahajan, F. Maiden, C. Man-Friel, F. Mansfield, S. Marsden, R. Martin, S. Mazzi, R. McAdams, G. McArdle, K.G. McClements, J. McClenaghan, D. McConville, K. McKay, C. McKnight, P. McKnight, A. McLean, B.F. McMillan, A. McShee, J. Measures, N. Mehay, C.A. Michael, F. Militello, D. Morbey, S. Mordijck, D. Moulton, O. Myatra, A.O. Nelson, M. Nicassio, M.G. O’Mullane, H.J.C. Oliver, P. Ollus, T. Osborne, N. Osborne, E. Parr, B. Parry, B.S. Patel, D. Payne, C. Paz-Soldan, A. Phelps, L. Piron, C. Piron, G. Prechel, M. Price, B. Pritchard, R. Proudfoot, H. Reimerdes, T. Rhodes, P. Richardson, J. Riquezes, J.F. Rivero-Rodriguez, C.M. Roach, M. Robson, K. Ronald, E. Rose, P. Ryan, D. Ryan, S. Saarelma, S. Sabbagh, R. Sarwar, P. Saunders, O. Sauter, R. Scannell, T. Schuett, R. Seath, R. Sharma, P. Shi, B. Sieglin, M. Simmonds, J. Smith, A. Smith, V. A. Soukhanovskii, D. Speirs, G. Staebler, R. Stephen, P. Stevenson, J. Stobbs, M. Stott, C. Stroud, C. Tame, C. Theiler, N. Thomas-Davies, A.J. Thornton, M. Tobin, M. Vallar, R.G.L. Vann, L. Velarde, K. Verhaegh, E. Viezzer, C. Vincent, G. Voss, M. Warr, W. Wehner, S. Wiesen, T.A. Wijkamp, D. Wilkins, T. Williams, T. Wilson, H.R. Wilson, H. Wong, M. Wood, and V. Zamkovska

Subjects
MAST upgrade, exhaust, integrated scenarios, alternative divertors, pedestal, fast ions, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Recent results from MAST Upgrade are presented, emphasising understanding the capabilities of this new device and deepening understanding of key physics issues for the operation of ITER and the design of future fusion power plants. The impact of MHD instabilities on fast ion confinement have been studied, including the first observation of fast ion losses correlated with Compressional and Global Alfvén Eigenmodes. High-performance plasma scenarios have been developed by tailoring the early plasma current ramp phase to avoid internal reconnection events, resulting in a more monotonic q profile with low central shear. The impact of m / n = 3/2, 2/1 and 1/1 modes on thermal plasma confinement and rotation profiles has been quantified, and scenarios optimised to avoid them have transiently reached values of normalised beta approaching 4.2. In pedestal and ELM physics, a maximum pedestal top temperature of ∼350 eV has been achieved, exceeding the value achieved on MAST at similar heating power. Mitigation of type-I ELMs with n = 1 RMPs has been observed. Studies of plasma exhaust have concentrated on comparing conventional and Super-X divertor configurations, while X-point target, X-divertor and snowflake configurations have been developed and studied in parallel. In L-mode discharges, the separatrix density required to detach the outer divertors is approximately a factor 2 lower in the Super-X than the conventional configuration, in agreement with simulations. Detailed analysis of spectroscopy data from studies of the Super-X configuration reveal the importance of including plasma-molecule interactions and D _2 Fulcher band emission to properly quantify the rates of ionisation, plasma-molecule interactions and volumetric recombination processes governing divertor detachment. In H-mode with conventional and Super-X configurations, the outer divertors are attached in the former and detached in the latter with no impact on core or pedestal confinement.

Published
2024
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2. Plasma Facing Component Characterization and Correlation With Plasma Conditions in Lithium Tokamak Experiment-β

Author

Richard Majeski, E. Merino, Bruce E. Koel, Drew Elliott, P.E. Hughes, Robert Kaita, A. Maan, Evan Ostrowski, Dennis Boyle, David Donovan, Filippo Scotti, V. A. Soukhanovskii, T. M. Biewer, Robert Lunsford, and T. A. Kozub

Subjects
Nuclear and High Energy Physics, Materials science, Hydrogen, Binding energy, Analytical chemistry, chemistry.chemical_element, Plasma, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, chemistry.chemical_compound, X-ray photoelectron spectroscopy, chemistry, Lithium hydride, 0103 physical sciences, Lithium Tokamak Experiment, Plasma diagnostics, Lithium
Abstract

Lithium coatings in the Lithium Tokamak eXperiment (LTX) led to flat temperature profiles. The flat temperature profiles were observed along with a hot, low density edge, implying a broad, collisionless scrape-off layer (SOL). Additionally, in vacuo X-ray photoelectron spectroscopy (XPS) measurements established that lithium coatings evaporatively deposited onto high-Z plasma facing components (PFCs) became oxidized while retaining the ability to achieve good plasma performance long after lithium was applied to the PFCs. Longstanding theory predicted flat temperature profiles with low recycling walls, which was presumed to be due to hydrogen binding with elemental lithium to form lithium hydride. The presence of oxidized lithium, however, raised questions regarding the exact mechanism of hydrogen retention in LTX. To investigate these questions, the upgraded facility LTX- $\beta $ includes a new sample exposure probe (SEP) for more detailed in vacuo analysis of PFC samples. The SEP is equipped with a vacuum suitcase capable of transporting samples representative of the LTX- $\beta $ outer midplane PFCs to a stand-alone XPS system while maintaining pressures lower than the LTX- $\beta $ base vacuum to limit the contamination between sample exposure and analysis. The low-energy resolution XPS system used in past experiments could only enable the determination of elemental percentages on the PFC sample surfaces. Because the new XPS system has higher energy resolution, it is more direct to assign chemical compounds to the measured binding energies. This capability has been confirmed by comparing XPS data from PFC test samples with measurements using a commercial high-resolution XPS system. Quartz crystal microbalances (QCMs) were used to quantify the thickness of the deposited lithium on the LTX- $\beta $ PFCs. This article describes the application of the SEP to characterize the PFC surfaces using XPS and their relationship to plasma conditions.

Published
2020

3. Initial Results From the Newly Upgraded LTX-β

Author

Bruce E. Koel, Jay Anderson, Drew Elliott, Robert Kaita, Christopher Hansen, Filippo Scotti, Ronald E. Bell, A. Maan, V. A. Soukhanovskii, Dennis Boyle, Robert Lunsford, David Donovan, P. E. Hughes, S. Kubota, Leonid E. Zakharov, T. M. Biewer, and Richard Majeski

Subjects
Nuclear and High Energy Physics, Tokamak, Toroid, Materials science, chemistry.chemical_element, Field strength, Condensed Matter Physics, 01 natural sciences, Neutral beam injection, 010305 fluids & plasmas, law.invention, chemistry, law, 0103 physical sciences, Lithium Tokamak Experiment, Electron temperature, Lithium, Atomic physics, Beam (structure)
Abstract

LTX-β, the upgraded Lithium Tokamak Experiment, recently began its first campaign with a goal to study the transport properties of gradient-free electron temperature profile equilibria with increased toroidal field and neutral beam injection. The temperature-gradient-free equilibria in LTX were enabled by the lithium plasma-facing surface. To make the lithium surface conditions more consistent for LTX-β, a new, faster lithium evaporator system has been developed. The toroidal magnetic field has been nearly doubled to ≥0.3 T. Auxiliary heating and fueling with a high flux (35 A, 20 kV) neutral beam has begun. The beam provides core fueling without cold edge neutrals, to test whether flat temperature profiles can be sustained, and makes possible core ion temperature measurements via charge exchange recombination spectroscopy. Neutral beam fueling has been demonstrated with increases in line-integrated density. The coupling of the beam matches well with NUBEAM predictions for shine through. Improved performance has been observed following lithium evaporative coatings and an increase in field strength.

Published
2020

4. Hydrogen retention in lithium on metallic walls from 'in vacuo' analysis in LTX and implications for high-Z plasma-facing components in NSTX-U

Author

Robert Kaita, Jean Paul Allain, R. Majeski, C.H. Skinner, Dennis Boyle, J. C. Schmitt, Angela M. Capece, Bruce E. Koel, Michael Jaworski, F. Bedoya, M. Lucia, R.E. Bell, J.P. Roszell, Filippo Scotti, and V. A. Soukhanovskii

Subjects
Materials science, Hydrogen, Mechanical Engineering, Divertor, Analytical chemistry, chemistry.chemical_element, Magnetic confinement fusion, Plasma, 01 natural sciences, 010305 fluids & plasmas, chemistry.chemical_compound, Nuclear Energy and Engineering, chemistry, Deuterium, 0103 physical sciences, Lithium Tokamak Experiment, General Materials Science, Lithium oxide, Graphite, 010306 general physics, Civil and Structural Engineering
Abstract

The application of lithium to plasma-facing components (PFCs) has long been used as a technique for wall conditioning in magnetic confinement devices to improve plasma performance. Determining the characteristics of PFCs at the time of exposure to the plasma, however, is difficult because they can only be analyzed after venting the vacuum vessel and removing them at the end of an operational period. The Materials Analysis and Particle Probe (MAPP) addresses this problem by enabling PFC samples to be exposed to plasmas, and then withdrawn into an analysis chamber without breaking vacuum. The MAPP system was used to introduce samples that matched the metallic PFCs of the Lithium Tokamak Experiment (LTX). Lithium that was subsequently evaporated onto the walls also covered the MAPP samples, which were then subject to LTX discharges. In vacuo extraction and analysis of the samples indicated that lithium oxide formed on the PFCs, but improved plasma performance persisted in LTX. The reduced recycling this suggests is consistent with separate surface science experiments that demonstrated deuterium retention in the presence of lithium oxide films. Since oxygen decreases the thermal stability of the deuterium in the film, the release of deuterium was observed below the lithium deuteride dissociation temperature. This may explain what occurred when lithium was applied to the surface of the NSTX Liquid Lithium Divertor (LLD). The LLD had segments with individual heaters, and the deuterium-alpha emission was clearly lower in the cooler regions. The plan for NSTX-U is to replace the graphite tiles with high-Z PFCs, and apply lithium to their surfaces with lithium evaporation. Experiments with lithium coatings on such PFCs suggest that deuterium could still be retained if lithium compounds form, but limiting their surface temperatures may be necessary.

Published
2017

5. Global modeling of wall material migration following boronization in NSTX-U

Author

F. Bedoya, Filippo Scotti, V. A. Soukhanovskii, Klaus Schmid, M. A. Jaworski, C. H. Skinner, and J.H. Nichols

Subjects
inorganic chemicals, 010302 applied physics, Nuclear and High Energy Physics, Glow discharge, Materials science, Tokamak, Materials Science (miscellaneous), Divertor, chemistry.chemical_element, Plasma, lcsh:TK9001-9401, 01 natural sciences, 010305 fluids & plasmas, law.invention, Nuclear Energy and Engineering, chemistry, law, Impurity, 0103 physical sciences, lcsh:Nuclear engineering. Atomic power, Deposition (phase transition), Thin film, Atomic physics, Boron
Abstract

Boronization is commonly utilized in tokamaks to suppress intrinsic impurities, most notably oxygen from residual water vapor. However, this is a temporary solution, as oxygen levels typically return to pre-boronization levels following repeated plasma exposure. The global impurity migration model WallDYN has been applied to the post-boronization surface impurity evolution in NSTX-U. A “Thin Film Model” has been incorporated into WallDYN to handle spatially inhomogeneous conditioning films of varying thicknesses, together with an empirical boron conditioning model for the NSTX-U glow discharge boronization process. The model qualitatively reproduces the spatial distribution of boron in the NSTX-U vessel, the spatially-resolved divertor emission pattern, and the increase in oxygen levels following boronization. The simulations suggest that oxygen is primarily sourced from wall locations without heavy plasma flux or significant boron deposition, namely the lower and upper passive plates and the lower private flux zone.

Published
2019

6. DIII-D research towards establishing the scientific basis for future fusion reactors

Author

L. Abadie, T. W. Abrams, J. Ahn, T. Akiyama, P. Aleynikov, J. Allcock, E. O. Allen, S. Allen, J. P. Anderson, A. Ashourvan, M. E. Austin, J. Bak, K. K. Barada, N. Barbour, L. Bardoczi, J. Barr, J. L. Barton, E. M. Bass, D. Battaglia, L. R. Baylor, J. Beckers, E. A. Belli, J. W. Berkery, N. Bertelli, J. M. Bialek, J. A. Boedo, R. L. Boivin, P. T. Bonoli, A. Bortolon, M. D. Boyer, R. E. Brambila, B. Bray, D. P. Brennan, A. R. Briesemeister, S. A. Bringuier, M. W. Brookman, D. L. Brower, B. R. Brown, W. D. Brown, D. Buchenauer, M. G. Burke, K. H. Burrell, J. Butt, R. J. Buttery, I. Bykov, J. M. Candy, J. M. Canik, N. M. Cao, L. Carbajal Gomez, L. C. Carlson, T. N. Carlstrom, T. A. Carter, W. Cary, L. Casali, M. Cengher, V. S. Chan, B. Chen, J. Chen, M. Chen, R. Chen, Xi Chen, W. Choi, C. Chrobak, C. Chrystal, R. M. Churchill, M. Cianciosa, C. F. Clauser, M. Clement, J. Coburn, C. S. Collins, A. W. Cooper, B. M. Covele, J. W. Crippen, N. A. Crocker, B. J. Crowley, A. Dal Molin, E. M. Davis, J. S. deGrassie, C. A. del-Castillo-Negrete, L. F. Delgado-Aparicio, A. Diallo, S. J. Diem, R. Ding, S. Ding, W. Ding, J. L. Doane, D. C. Donovan, J. Drake, D. Du, H. Du, X. Du, V. Duarte, J. D. Duran, N. W. Eidietis, D. Elder, D. Eldon, W. Elwasif, T. E. Ely, K. M. Eng, K. Engelhorn, D. Ennis, K. Erickson, D. R. Ernst, T. E. Evans, M. E. Fenstermacher, N. M. Ferraro, J. R. Ferron, D. F. Finkenthal, P. A. Fisher, B. Fishler, S. M. Flanagan, J. A. Fooks, L. Frassinetti, H. G. Frerichs, Y. Fu, T. Fulop, Q. Gao, F. Garcia, A. M. Garofalo, A. Gattuso, L. Giacomelli, E. M. Giraldez, C. Giroud, F. Glass, P. Gohil, X. Gong, Y. A. Gorelov, R. S. Granetz, D. L. Green, C. M. Greenfield, B. A. Grierson, R. J. Groebner, W. H. Grosnickle, M. Groth, H. J. Grunloh, H. Y. Guo, W. Guo, J. Guterl, R. C. Hager, S. Hahn, F. D. Halpern, H. Han, M. J. Hansink, J. M. Hanson, J. Harris, S. R. Haskey, D. R. Hatch, W. W. Heidbrink, J. Herfindal, D. N. Hill, M. D. Hill, E. T. Hinson, C. T. Holcomb, C. G. Holland, L. D. Holland, E. M. Hollmann, A. M. Holm, R. Hong, M. Hoppe, S. Houshmandyar, J. Howard, N. T. Howard, Q. Hu, W. Hu, H. Huang, J. Huang, Y. Huang, G. A. Hughes, J. Hughes, D. A. Humphreys, A. W. Hyatt, K. Ida, V. Igochine, Y. In, S. Inoue, A. Isayama, R. C. Isler, V. A. Izzo, M. R. Jackson, A. E. Jarvinen, Y. Jeon, H. Ji, X. Jian, R. Jimenez, C. A. Johnson, I. Joseph, D. N. Kaczala, D. H. Kaplan, J. Kates-Harbeck, A. G. Kellman, D. H. Kellman, C. E. Kessel, K. Khumthong, C. C. Kim, H. Kim, J. Kim, K. Kim, S. H. Kim, W. Kimura, J. R. King, A. Kirk, K. Kleijwegt, M. Knolker, A. Kohn, E. Kolemen, M. Kostuk, G. J. Kramer, P. Kress, D. M. Kriete, R. J. La Haye, F. M. Laggner, H. Lan, M. J. Lanctot, R. Lantsov, L. L. Lao, C. J. Lasnier, C. Lau, K. Law, D. Lawrence, J. Le, R. L. Lee, M. Lehnen, R. Leon, A. W. Leonard, M. Lesher, J. A. Leuer, G. Li, K. Li, K. T. Liao, Z. Lin, C. Liu, F. Liu, Y. Liu, Z. Liu, S. Loch, N. C. Logan, J. M. Lohr, J. Lore, T. C. Luce, N. C. Luhmann, R. Lunsford, C. Luo, Z. Luo, L. Lupin-Jimenez, A. Lvovskiy, B. C. Lyons, X. Ma, R. Maingi, M. A. Makowski, P. Mantica, M. Manuel, M. W. Margo, A. Marinoni, E. Marmar, W. C. Martin, R. L. Masline, G. K. Matsunaga, D. M. Mauzey, P. S. Mauzey, J. T. Mcclenaghan, G. R. Mckee, A. G. Mclean, H. S. Mclean, E. Meier, S. J. Meitner, J. E. Menard, O. Meneghini, G. Merlo, W. H. Meyer, D. C. Miller, W. J. Miller, C. P. Moeller, K. J. Montes, M. A. Morales, S. Mordijck, A. Moser, R. A. Moyer, S. A. Muller, S. Munaretto, M. Murakami, C. J. Murphy, C. M. Muscatello, C. E. Myers, A. Nagy, G. A. Navratil, R. M. Nazikian, A. L. Neff, T. F. Neiser, A. Nelson, P. Nguyen, R. Nguyen, J. H. Nichols, M. Nocente, R. E. Nygren, R. C. O'Neill, T. Odstrcil, S. Ohdachi, M. Okabayashi, E. Olofsson, M. Ono, D. M. Orlov, T. H. Osborne, N. A. Pablant, D. C. Pace, R. R. Paguio, A. Pajares Martinez, C. Pan, A. Pankin, J. M. Park, J. Park, Y. Park, C. T. Parker, S. E. Parker, P. B. Parks, C. J. Pawley, C. A. Paz-Soldan, W. A. Peebles, B. G. Penaflor, T. W. Petrie, C. C. Petty, Y. Peysson, A. Y. Pigarov, D. A. Piglowski, R. I. Pinsker, P. Piovesan, N. Piper, R. A. Pitts, J. D. Pizzo, M. L. Podesta, F. M. Poli, D. Ponce, M. Porkolab, G. D. Porter, R. Prater, J. Qian, O. Ra, T. Rafiq, R. Raman, C. Rand, G. C. Randall, J. M. Rauch, C. Rea, M. L. Reinke, J. Ren, Q. Ren, Y. Ren, T. L. Rhodes, J. Rice, T. D. Rognlien, J. C. Rost, W. L. Rowan, D. L. Rudakov, A. Salmi, B. S. Sammuli, C. M. Samuell, A. M. Sandorfi, C. Sang, O. J. Sauter, D. P. Schissel, L. Schmitz, O. Schmitz, E. J. Schuster, J. T. Scoville, A. Seltzman, I. Sfiligoi, M. Shafer, H. Shen, T. Shi, D. Shiraki, H. Si, D. R. Smith, S. P. Smith, J. A. Snipes, P. B. Snyder, E. R. Solano, W. M. Solomon, A. C. Sontag, V. A. Soukhanovskii, D. A. Spong, W. M. Stacey, G. M. Staebler, L. Stagner, B. Stahl, P. C. Stangeby, T. J. Stoltzfus-Dueck, D. P. Stotler, E. J. Strait, D. Su, L. E. Sugiyama, A. A. Sulyman, Y. Sun, C. Sung, W. A. Suttrop, Y. Suzuki, A. Svyatkovskiy, R. M. Sweeney, S. Taimourzadeh, M. Takechi, T. Tala, H. Tan, S. Tang, X. Tang, D. Taussig, G. Taylor, N. Z. Taylor, T. S. Taylor, A. Teklu, D. M. Thomas, M. B. Thomas, K. E. Thome, A. R. Thorman, R. A. Tinguely, B. J. Tobias, J. F. Tooker, H. Torreblanca, A. Torrezan De Sousa, G. L. Trevisan, D. Truong, F. Turco, A. D. Turnbull, E. A. Unterberg, P. Vaezi, P. J. Vail, M. A. Van Zeeland, M. Velasco Enriquez, M. C. Venkatesh, B. S. Victor, F. Volpe, M. R. Wade, M. L. Walker, J. R. Wall, G. M. Wallace, R. E. Waltz, G. Wang, H. Wang, Y. Wang, Z. Wang, F. Wang, S. H. Ward, J. G. Watkins, M. Watkins, W. P. Wehner, M. Weiland, D. B. Weisberg, A. S. Welander, A. E. White, R. B. White, D. Whyte, T. A. Wijkamp, R. Wilcox, T. Wilks, H. R. Wilson, A. Wingen, E. Wolfe, M. Wu, W. Wu, S. J. Wukitch, T. Xia, N. Xiang, B. Xiao, R. Xie, G. Xu, H. Xu, X. Xu, Z. Yan, Q. Yang, X. Yang, M. Yoshida, G. Yu, J. H. Yu, M. Yu, S. A. Zamperini, L. Zeng, B. Zhao, D. Zhao, H. Zhao, Y. Zhao, Y. Zhu, B. Zywicki, Abadie, L, Abrams, T, Ahn, J, Akiyama, T, Aleynikov, P, Allcock, J, Allen, E, Allen, S, Anderson, J, Ashourvan, A, Austin, M, Bak, J, Barada, K, Barbour, N, Bardoczi, L, Barr, J, Barton, J, Bass, E, Battaglia, D, Baylor, L, Beckers, J, Belli, E, Berkery, J, Bertelli, N, Bialek, J, Boedo, J, Boivin, R, Bonoli, P, Bortolon, A, Boyer, M, Brambila, R, Bray, B, Brennan, D, Briesemeister, A, Bringuier, S, Brookman, M, Brower, D, Brown, B, Brown, W, Buchenauer, D, Burke, M, Burrell, K, Butt, J, Buttery, R, Bykov, I, Candy, J, Canik, J, Cao, N, Carbajal Gomez, L, Carlson, L, Carlstrom, T, Carter, T, Cary, W, Casali, L, Cengher, M, Chan, V, Chen, B, Chen, J, Chen, M, Chen, R, Chen, X, Choi, W, Chrobak, C, Chrystal, C, Churchill, R, Cianciosa, M, Clauser, C, Clement, M, Coburn, J, Collins, C, Cooper, A, Covele, B, Crippen, J, Crocker, N, Crowley, B, Dal Molin, A, Davis, E, Degrassie, J, del-Castillo-Negrete, C, Delgado-Aparicio, L, Diallo, A, Diem, S, Ding, R, Ding, S, Ding, W, Doane, J, Donovan, D, Drake, J, Du, D, Du, H, Du, X, Duarte, V, Duran, J, Eidietis, N, Elder, D, Eldon, D, Elwasif, W, Ely, T, Eng, K, Engelhorn, K, Ennis, D, Erickson, K, Ernst, D, Evans, T, Fenstermacher, M, Ferraro, N, Ferron, J, Finkenthal, D, Fisher, P, Fishler, B, Flanagan, S, Fooks, J, Frassinetti, L, Frerichs, H, Fu, Y, Fulop, T, Gao, Q, Garcia, F, Garofalo, A, Gattuso, A, Giacomelli, L, Giraldez, E, Giroud, C, Glass, F, Gohil, P, Gong, X, Gorelov, Y, Granetz, R, Green, D, Greenfield, C, Grierson, B, Groebner, R, Grosnickle, W, Groth, M, Grunloh, H, Guo, H, Guo, W, Guterl, J, Hager, R, Hahn, S, Halpern, F, Han, H, Hansink, M, Hanson, J, Harris, J, Haskey, S, Hatch, D, Heidbrink, W, Herfindal, J, Hill, D, Hill, M, Hinson, E, Holcomb, C, Holland, C, Holland, L, Hollmann, E, Holm, A, Hong, R, Hoppe, M, Houshmandyar, S, Howard, J, Howard, N, Hu, Q, Hu, W, Huang, H, Huang, J, Huang, Y, Hughes, G, Hughes, J, Humphreys, D, Hyatt, A, Ida, K, Igochine, V, In, Y, Inoue, S, Isayama, A, Isler, R, Izzo, V, Jackson, M, Jarvinen, A, Jeon, Y, Ji, H, Jian, X, Jimenez, R, Johnson, C, Joseph, I, Kaczala, D, Kaplan, D, Kates-Harbeck, J, Kellman, A, Kellman, D, Kessel, C, Khumthong, K, Kim, C, Kim, H, Kim, J, Kim, K, Kim, S, Kimura, W, King, J, Kirk, A, Kleijwegt, K, Knolker, M, Kohn, A, Kolemen, E, Kostuk, M, Kramer, G, Kress, P, Kriete, D, La Haye, R, Laggner, F, Lan, H, Lanctot, M, Lantsov, R, Lao, L, Lasnier, C, Lau, C, Law, K, Lawrence, D, Le, J, Lee, R, Lehnen, M, Leon, R, Leonard, A, Lesher, M, Leuer, J, Li, G, Li, K, Liao, K, Lin, Z, Liu, C, Liu, F, Liu, Y, Liu, Z, Loch, S, Logan, N, Lohr, J, Lore, J, Luce, T, Luhmann, N, Lunsford, R, Luo, C, Luo, Z, Lupin-Jimenez, L, Lvovskiy, A, Lyons, B, Ma, X, Maingi, R, Makowski, M, Mantica, P, Manuel, M, Margo, M, Marinoni, A, Marmar, E, Martin, W, Masline, R, Matsunaga, G, Mauzey, D, Mauzey, P, Mcclenaghan, J, Mckee, G, Mclean, A, Mclean, H, Meier, E, Meitner, S, Menard, J, Meneghini, O, Merlo, G, Meyer, W, Miller, D, Miller, W, Moeller, C, Montes, K, Morales, M, Mordijck, S, Moser, A, Moyer, R, Muller, S, Munaretto, S, Murakami, M, Murphy, C, Muscatello, C, Myers, C, Nagy, A, Navratil, G, Nazikian, R, Neff, A, Neiser, T, Nelson, A, Nguyen, P, Nguyen, R, Nichols, J, Nocente, M, Nygren, R, O'Neill, R, Odstrcil, T, Ohdachi, S, Okabayashi, M, Olofsson, E, Ono, M, Orlov, D, Osborne, T, Pablant, N, Pace, D, Paguio, R, Pajares Martinez, A, Pan, C, Pankin, A, Park, J, Park, Y, Parker, C, Parker, S, Parks, P, Pawley, C, Paz-Soldan, C, Peebles, W, Penaflor, B, Petrie, T, Petty, C, Peysson, Y, Pigarov, A, Piglowski, D, Pinsker, R, Piovesan, P, Piper, N, Pitts, R, Pizzo, J, Podesta, M, Poli, F, Ponce, D, Porkolab, M, Porter, G, Prater, R, Qian, J, Ra, O, Rafiq, T, Raman, R, Rand, C, Randall, G, Rauch, J, Rea, C, Reinke, M, Ren, J, Ren, Q, Ren, Y, Rhodes, T, Rice, J, Rognlien, T, Rost, J, Rowan, W, Rudakov, D, Salmi, A, Sammuli, B, Samuell, C, Sandorfi, A, Sang, C, Sauter, O, Schissel, D, Schmitz, L, Schmitz, O, Schuster, E, Scoville, J, Seltzman, A, Sfiligoi, I, Shafer, M, Shen, H, Shi, T, Shiraki, D, Si, H, Smith, D, Smith, S, Snipes, J, Snyder, P, Solano, E, Solomon, W, Sontag, A, Soukhanovskii, V, Spong, D, Stacey, W, Staebler, G, Stagner, L, Stahl, B, Stangeby, P, Stoltzfus-Dueck, T, Stotler, D, Strait, E, Su, D, Sugiyama, L, Sulyman, A, Sun, Y, Sung, C, Suttrop, W, Suzuki, Y, Svyatkovskiy, A, Sweeney, R, Taimourzadeh, S, Takechi, M, Tala, T, Tan, H, Tang, S, Tang, X, Taussig, D, Taylor, G, Taylor, N, Taylor, T, Teklu, A, Thomas, D, Thomas, M, Thome, K, Thorman, A, Tinguely, R, Tobias, B, Tooker, J, Torreblanca, H, Torrezan De Sousa, A, Trevisan, G, Truong, D, Turco, F, Turnbull, A, Unterberg, E, Vaezi, P, Vail, P, Van Zeeland, M, Velasco Enriquez, M, Venkatesh, M, Victor, B, Volpe, F, Wade, M, Walker, M, Wall, J, Wallace, G, Waltz, R, Wang, G, Wang, H, Wang, Y, Wang, Z, Wang, F, Ward, S, Watkins, J, Watkins, M, Wehner, W, Weiland, M, Weisberg, D, Welander, A, White, A, White, R, Whyte, D, Wijkamp, T, Wilcox, R, Wilks, T, Wilson, H, Wingen, A, Wolfe, E, Wu, M, Wu, W, Wukitch, S, Xia, T, Xiang, N, Xiao, B, Xie, R, Xu, G, Xu, H, Xu, X, Yan, Z, Yang, Q, Yang, X, Yoshida, M, Yu, G, Yu, J, Yu, M, Zamperini, S, Zeng, L, Zhao, B, Zhao, D, Zhao, H, Zhao, Y, Zhu, Y, and Zywicki, B

Subjects
Physics, Nuclear and High Energy Physics, fusion, model, Tokamak, DIII-D, Divertor, Mechanics, Plasma, Fusion power, Dissipation, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, Pedestal, Heat flux, law, Physics::Plasma Physics, 0103 physical sciences, 010306 general physics, tokamak, plasma, energy
Abstract

DIII-D research is addressing critical challenges in preparation for ITER and the next generation of fusion devices through focusing on plasma physics fundamentals that underpin key fusion goals, understanding the interaction of disparate core and boundary plasma physics, and developing integrated scenarios for achieving high performance fusion regimes. Fundamental investigations into fusion energy science find that anomalous dissipation of runaway electrons (RE) that arise following a disruption is likely due to interactions with RE-driven kinetic instabilities, some of which have been directly observed, opening a new avenue for RE energy dissipation using naturally excited waves. Dimensionless parameter scaling of intrinsic rotation and gyrokinetic simulations give a predicted ITER rotation profile with significant turbulence stabilization. Coherence imaging spectroscopy confirms near sonic flow throughout the divertor towards the target, which may account for the convection-dominated parallel heat flux. Core-boundary integration studies show that the small angle slot divertor achieves detachment at lower density and extends plasma cooling across the divertor target plate, which is essential for controlling heat flux and erosion. The Super H-mode regime has been extended to high plasma current (2.0 MA) and density to achieve very high pedestal pressures (~30 kPa) and stored energy (3.2 MJ) with H 98y2 ≈ 1.6–2.4. In scenario work, the ITER baseline Q = 10 scenario with zero injected torque is found to have a fusion gain metric independent of current between q 95 = 2.8–3.7, and a lower limit of pedestal rotation for RMP ELM suppression has been found. In the wide pedestal QH-mode regime that exhibits improved performance and no ELMs, the start-up counter torque has been eliminated so that the entire discharge uses ≈0 injected torque and the operating space is more ITER-relevant. Finally, the high- (⩽3.8) hybrid scenario has been extended to the high-density levels necessary for radiating divertor operation, achieving ~40% divertor heat flux reduction using either argon or neon with P tot up to 15 MW.

Published
2019

7. Modeling snowflake divertors in MAST-U tokamak using UEDGE code

Author

Maxim Umansky, Alexander Khrabry, V. A. Soukhanovskii, David Moulton, J. R. Harrison, and T.D. Rognlien

Subjects
Nuclear and High Energy Physics, Multi-fluid model, Tokamak, Materials science, Plasma parameters, Materials Science (miscellaneous), Divertor, Snowflake divertor, Plasma, lcsh:TK9001-9401, Reducing heat load, law.invention, Magnetic field, Nuclear Energy and Engineering, Heat flux, law, Numerical modeling, lcsh:Nuclear engineering. Atomic power, Advanced divertor, Snowflake, Atomic physics, Churning mode, Carbon impurities
Abstract

In a snowflake (SF) divertor, two magnetic field nulls are placed close to each other creating four strike points (SPs) cf. two in a standard single-null (SN) divertor. In preparation to MAST-U experiments, magnetic configurations with SN and SF divertors located symmetrically at the top and at the bottom of the tokamak were modeled using a two-dimensional multi-fluid code UEDGE with a full plasma transport model featuring charge-state-resolved sputtered carbon impurities. SF configurations with various relative locations of the nulls and small null separation were considered. The complex interplay of the plasma transport and magnetic configurations was comprehensively studied using a simple model for the theoretically predicted fast plasma mixing (the “churning” mode) in the two-null SF region. The modeling results show that: 1) SF-plus and SF-minus configurations with closely located nulls produce same plasma parameters and heat fluxes at same SPs; 2) SF divertors approach the outer and inner SP detachment conditions at lower upstream density w.r.t. SN divertor; 3) heat flux profiles at primary SPs are substantially broadened and peak values are reduced in SF configurations w.r.t. SN divertor; this effect becomes more pronounced with the fast plasma mixing increase; 4) with the SF mixing, secondary SPs receive up to 10% (each) of the heat flux to the primary outer SP.

Published
2021

8. DIII-D research towards establishing the scientific basis for future fusion reactors

Author

Abadie, L, Abrams, T, Ahn, J, Akiyama, T, Aleynikov, P, Allcock, J, Allen, E, Allen, S, Anderson, J, Ashourvan, A, Austin, M, Bak, J, Barada, K, Barbour, N, Bardoczi, L, Barr, J, Barton, J, Bass, E, Battaglia, D, Baylor, L, Beckers, J, Belli, E, Berkery, J, Bertelli, N, Bialek, J, Boedo, J, Boivin, R, Bonoli, P, Bortolon, A, Boyer, M, Brambila, R, Bray, B, Brennan, D, Briesemeister, A, Bringuier, S, Brookman, M, Brower, D, Brown, B, Brown, W, Buchenauer, D, Burke, M, Burrell, K, Butt, J, Buttery, R, Bykov, I, Candy, J, Canik, J, Cao, N, Carbajal Gomez, L, Carlson, L, Carlstrom, T, Carter, T, Cary, W, Casali, L, Cengher, M, Chan, V, Chen, B, Chen, J, Chen, M, Chen, R, Chen, X, Choi, W, Chrobak, C, Chrystal, C, Churchill, R, Cianciosa, M, Clauser, C, Clement, M, Coburn, J, Collins, C, Cooper, A, Covele, B, Crippen, J, Crocker, N, Crowley, B, Dal Molin, A, Davis, E, Degrassie, J, del-Castillo-Negrete, C, Delgado-Aparicio, L, Diallo, A, Diem, S, Ding, R, Ding, S, Ding, W, Doane, J, Donovan, D, Drake, J, Du, D, Du, H, Du, X, Duarte, V, Duran, J, Eidietis, N, Elder, D, Eldon, D, Elwasif, W, Ely, T, Eng, K, Engelhorn, K, Ennis, D, Erickson, K, Ernst, D, Evans, T, Fenstermacher, M, Ferraro, N, Ferron, J, Finkenthal, D, Fisher, P, Fishler, B, Flanagan, S, Fooks, J, Frassinetti, L, Frerichs, H, Fu, Y, Fulop, T, Gao, Q, Garcia, F, Garofalo, A, Gattuso, A, Giacomelli, L, Giraldez, E, Giroud, C, Glass, F, Gohil, P, Gong, X, Gorelov, Y, Granetz, R, Green, D, Greenfield, C, Grierson, B, Groebner, R, Grosnickle, W, Groth, M, Grunloh, H, Guo, H, Guo, W, Guterl, J, Hager, R, Hahn, S, Halpern, F, Han, H, Hansink, M, Hanson, J, Harris, J, Haskey, S, Hatch, D, Heidbrink, W, Herfindal, J, Hill, D, Hill, M, Hinson, E, Holcomb, C, Holland, C, Holland, L, Hollmann, E, Holm, A, Hong, R, Hoppe, M, Houshmandyar, S, Howard, J, Howard, N, Hu, Q, Hu, W, Huang, H, Huang, J, Huang, Y, Hughes, G, Hughes, J, Humphreys, D, Hyatt, A, Ida, K, Igochine, V, In, Y, Inoue, S, Isayama, A, Isler, R, Izzo, V, Jackson, M, Jarvinen, A, Jeon, Y, Ji, H, Jian, X, Jimenez, R, Johnson, C, Joseph, I, Kaczala, D, Kaplan, D, Kates-Harbeck, J, Kellman, A, Kellman, D, Kessel, C, Khumthong, K, Kim, C, Kim, H, Kim, J, Kim, K, Kim, S, Kimura, W, King, J, Kirk, A, Kleijwegt, K, Knolker, M, Kohn, A, Kolemen, E, Kostuk, M, Kramer, G, Kress, P, Kriete, D, La Haye, R, Laggner, F, Lan, H, Lanctot, M, Lantsov, R, Lao, L, Lasnier, C, Lau, C, Law, K, Lawrence, D, Le, J, Lee, R, Lehnen, M, Leon, R, Leonard, A, Lesher, M, Leuer, J, Li, G, Li, K, Liao, K, Lin, Z, Liu, C, Liu, F, Liu, Y, Liu, Z, Loch, S, Logan, N, Lohr, J, Lore, J, Luce, T, Luhmann, N, Lunsford, R, Luo, C, Luo, Z, Lupin-Jimenez, L, Lvovskiy, A, Lyons, B, Ma, X, Maingi, R, Makowski, M, Mantica, P, Manuel, M, Margo, M, Marinoni, A, Marmar, E, Martin, W, Masline, R, Matsunaga, G, Mauzey, D, Mauzey, P, Mcclenaghan, J, Mckee, G, Mclean, A, Mclean, H, Meier, E, Meitner, S, Menard, J, Meneghini, O, Merlo, G, Meyer, W, Miller, D, Miller, W, Moeller, C, Montes, K, Morales, M, Mordijck, S, Moser, A, Moyer, R, Muller, S, Munaretto, S, Murakami, M, Murphy, C, Muscatello, C, Myers, C, Nagy, A, Navratil, G, Nazikian, R, Neff, A, Neiser, T, Nelson, A, Nguyen, P, Nguyen, R, Nichols, J, Nocente, M, Nygren, R, O'Neill, R, Odstrcil, T, Ohdachi, S, Okabayashi, M, Olofsson, E, Ono, M, Orlov, D, Osborne, T, Pablant, N, Pace, D, Paguio, R, Pajares Martinez, A, Pan, C, Pankin, A, Park, J, Park, Y, Parker, C, Parker, S, Parks, P, Pawley, C, Paz-Soldan, C, Peebles, W, Penaflor, B, Petrie, T, Petty, C, Peysson, Y, Pigarov, A, Piglowski, D, Pinsker, R, Piovesan, P, Piper, N, Pitts, R, Pizzo, J, Podesta, M, Poli, F, Ponce, D, Porkolab, M, Porter, G, Prater, R, Qian, J, Ra, O, Rafiq, T, Raman, R, Rand, C, Randall, G, Rauch, J, Rea, C, Reinke, M, Ren, J, Ren, Q, Ren, Y, Rhodes, T, Rice, J, Rognlien, T, Rost, J, Rowan, W, Rudakov, D, Salmi, A, Sammuli, B, Samuell, C, Sandorfi, A, Sang, C, Sauter, O, Schissel, D, Schmitz, L, Schmitz, O, Schuster, E, Scoville, J, Seltzman, A, Sfiligoi, I, Shafer, M, Shen, H, Shi, T, Shiraki, D, Si, H, Smith, D, Smith, S, Snipes, J, Snyder, P, Solano, E, Solomon, W, Sontag, A, Soukhanovskii, V, Spong, D, Stacey, W, Staebler, G, Stagner, L, Stahl, B, Stangeby, P, Stoltzfus-Dueck, T, Stotler, D, Strait, E, Su, D, Sugiyama, L, Sulyman, A, Sun, Y, Sung, C, Suttrop, W, Suzuki, Y, Svyatkovskiy, A, Sweeney, R, Taimourzadeh, S, Takechi, M, Tala, T, Tan, H, Tang, S, Tang, X, Taussig, D, Taylor, G, Taylor, N, Taylor, T, Teklu, A, Thomas, D, Thomas, M, Thome, K, Thorman, A, Tinguely, R, Tobias, B, Tooker, J, Torreblanca, H, Torrezan De Sousa, A, Trevisan, G, Truong, D, Turco, F, Turnbull, A, Unterberg, E, Vaezi, P, Vail, P, Van Zeeland, M, Velasco Enriquez, M, Venkatesh, M, Victor, B, Volpe, F, Wade, M, Walker, M, Wall, J, Wallace, G, Waltz, R, Wang, G, Wang, H, Wang, Y, Wang, Z, Wang, F, Ward, S, Watkins, J, Watkins, M, Wehner, W, Weiland, M, Weisberg, D, Welander, A, White, A, White, R, Whyte, D, Wijkamp, T, Wilcox, R, Wilks, T, Wilson, H, Wingen, A, Wolfe, E, Wu, M, Wu, W, Wukitch, S, Xia, T, Xiang, N, Xiao, B, Xie, R, Xu, G, Xu, H, Xu, X, Yan, Z, Yang, Q, Yang, X, Yoshida, M, Yu, G, Yu, J, Yu, M, Zamperini, S, Zeng, L, Zhao, B, Zhao, D, Zhao, H, Zhao, Y, Zhu, Y, Zywicki, B, L. Abadie, T. W. Abrams, J. Ahn, T. Akiyama, P. Aleynikov, J. Allcock, E. O. Allen, S. Allen, J. P. Anderson, A. Ashourvan, M. E. Austin, J. Bak, K. K. Barada, N. Barbour, L. Bardoczi, J. Barr, J. L. Barton, E. M. Bass, D. Battaglia, L. R. Baylor, J. Beckers, E. A. Belli, J. W. Berkery, N. Bertelli, J. M. Bialek, J. A. Boedo, R. L. Boivin, P. T. Bonoli, A. Bortolon, M. D. Boyer, R. E. Brambila, B. Bray, D. P. Brennan, A. R. Briesemeister, S. A. Bringuier, M. W. Brookman, D. L. Brower, B. R. Brown, W. D. Brown, D. Buchenauer, M. G. Burke, K. H. Burrell, J. Butt, R. J. Buttery, I. Bykov, J. M. Candy, J. M. Canik, N. M. Cao, L. Carbajal Gomez, L. C. Carlson, T. N. Carlstrom, T. A. Carter, W. Cary, L. Casali, M. Cengher, V. S. Chan, B. Chen, J. Chen, M. Chen, R. Chen, Xi Chen, W. Choi, C. Chrobak, C. Chrystal, R. M. Churchill, M. Cianciosa, C. F. Clauser, M. Clement, J. Coburn, C. S. Collins, A. W. Cooper, B. M. Covele, J. W. Crippen, N. A. Crocker, B. J. Crowley, A. Dal Molin, E. M. Davis, J. S. deGrassie, C. A. del-Castillo-Negrete, L. F. Delgado-Aparicio, A. Diallo, S. J. Diem, R. Ding, S. Ding, W. Ding, J. L. Doane, D. C. Donovan, J. Drake, D. Du, H. Du, X. Du, V. Duarte, J. D. Duran, N. W. Eidietis, D. Elder, D. Eldon, W. Elwasif, T. E. Ely, K. M. Eng, K. Engelhorn, D. Ennis, K. Erickson, D. R. Ernst, T. E. Evans, M. E. Fenstermacher, N. M. Ferraro, J. R. Ferron, D. F. Finkenthal, P. A. Fisher, B. Fishler, S. M. Flanagan, J. A. Fooks, L. Frassinetti, H. G. Frerichs, Y. Fu, T. Fulop, Q. Gao, F. Garcia, A. M. Garofalo, A. Gattuso, L. Giacomelli, E. M. Giraldez, C. Giroud, F. Glass, P. Gohil, X. Gong, Y. A. Gorelov, R. S. Granetz, D. L. Green, C. M. Greenfield, B. A. Grierson, R. J. Groebner, W. H. Grosnickle, M. Groth, H. J. Grunloh, H. Y. Guo, W. Guo, J. Guterl, R. C. Hager, S. Hahn, F. D. Halpern, H. Han, M. J. Hansink, J. M. Hanson, J. Harris, S. R. Haskey, D. R. Hatch, W. W. Heidbrink, J. Herfindal, D. N. Hill, M. D. Hill, E. T. Hinson, C. T. Holcomb, C. G. Holland, L. D. Holland, E. M. Hollmann, A. M. Holm, R. Hong, M. Hoppe, S. Houshmandyar, J. Howard, N. T. Howard, Q. Hu, W. Hu, H. Huang, J. Huang, Y. Huang, G. A. Hughes, J. Hughes, D. A. Humphreys, A. W. Hyatt, K. Ida, V. Igochine, Y. In, S. Inoue, A. Isayama, R. C. Isler, V. A. Izzo, M. R. Jackson, A. E. Jarvinen, Y. Jeon, H. Ji, X. Jian, R. Jimenez, C. A. Johnson, I. Joseph, D. N. Kaczala, D. H. Kaplan, J. Kates-Harbeck, A. G. Kellman, D. H. Kellman, C. E. Kessel, K. Khumthong, C. C. Kim, H. Kim, J. Kim, K. Kim, S. H. Kim, W. Kimura, J. R. King, A. Kirk, K. Kleijwegt, M. Knolker, A. Kohn, E. Kolemen, M. Kostuk, G. J. Kramer, P. Kress, D. M. Kriete, R. J. La Haye, F. M. Laggner, H. Lan, M. J. Lanctot, R. Lantsov, L. L. Lao, C. J. Lasnier, C. Lau, K. Law, D. Lawrence, J. Le, R. L. Lee, M. Lehnen, R. Leon, A. W. Leonard, M. Lesher, J. A. Leuer, G. Li, K. Li, K. T. Liao, Z. Lin, C. Liu, F. Liu, Y. Liu, Z. Liu, S. Loch, N. C. Logan, J. M. Lohr, J. Lore, T. C. Luce, N. C. Luhmann, R. Lunsford, C. Luo, Z. Luo, L. Lupin-Jimenez, A. Lvovskiy, B. C. Lyons, X. Ma, R. Maingi, M. A. Makowski, P. Mantica, M. Manuel, M. W. Margo, A. Marinoni, E. Marmar, W. C. Martin, R. L. Masline, G. K. Matsunaga, D. M. Mauzey, P. S. Mauzey, J. T. Mcclenaghan, G. R. Mckee, A. G. Mclean, H. S. Mclean, E. Meier, S. J. Meitner, J. E. Menard, O. Meneghini, G. Merlo, W. H. Meyer, D. C. Miller, W. J. Miller, C. P. Moeller, K. J. Montes, M. A. Morales, S. Mordijck, A. Moser, R. A. Moyer, S. A. Muller, S. Munaretto, M. Murakami, C. J. Murphy, C. M. Muscatello, C. E. Myers, A. Nagy, G. A. Navratil, R. M. Nazikian, A. L. Neff, T. F. Neiser, A. Nelson, P. Nguyen, R. Nguyen, J. H. Nichols, M. Nocente, R. E. Nygren, R. C. O'Neill, T. Odstrcil, S. Ohdachi, M. Okabayashi, E. Olofsson, M. Ono, D. M. Orlov, T. H. Osborne, N. A. Pablant, D. C. Pace, R. R. Paguio, A. Pajares Martinez, C. Pan, A. Pankin, J. M. Park, J. Park, Y. Park, C. T. Parker, S. E. Parker, P. B. Parks, C. J. Pawley, C. A. Paz-Soldan, W. A. Peebles, B. G. Penaflor, T. W. Petrie, C. C. Petty, Y. Peysson, A. Y. Pigarov, D. A. Piglowski, R. I. Pinsker, P. Piovesan, N. Piper, R. A. Pitts, J. D. Pizzo, M. L. Podesta, F. M. Poli, D. Ponce, M. Porkolab, G. D. Porter, R. Prater, J. Qian, O. Ra, T. Rafiq, R. Raman, C. Rand, G. C. Randall, J. M. Rauch, C. Rea, M. L. Reinke, J. Ren, Q. Ren, Y. Ren, T. L. Rhodes, J. Rice, T. D. Rognlien, J. C. Rost, W. L. Rowan, D. L. Rudakov, A. Salmi, B. S. Sammuli, C. M. Samuell, A. M. Sandorfi, C. Sang, O. J. Sauter, D. P. Schissel, L. Schmitz, O. Schmitz, E. J. Schuster, J. T. Scoville, A. Seltzman, I. Sfiligoi, M. Shafer, H. Shen, T. Shi, D. Shiraki, H. Si, D. R. Smith, S. P. Smith, J. A. Snipes, P. B. Snyder, E. R. Solano, W. M. Solomon, A. C. Sontag, V. A. Soukhanovskii, D. A. Spong, W. M. Stacey, G. M. Staebler, L. Stagner, B. Stahl, P. C. Stangeby, T. J. Stoltzfus-Dueck, D. P. Stotler, E. J. Strait, D. Su, L. E. Sugiyama, A. A. Sulyman, Y. Sun, C. Sung, W. A. Suttrop, Y. Suzuki, A. Svyatkovskiy, R. M. Sweeney, S. Taimourzadeh, M. Takechi, T. Tala, H. Tan, S. Tang, X. Tang, D. Taussig, G. Taylor, N. Z. Taylor, T. S. Taylor, A. Teklu, D. M. Thomas, M. B. Thomas, K. E. Thome, A. R. Thorman, R. A. Tinguely, B. J. Tobias, J. F. Tooker, H. Torreblanca, A. Torrezan De Sousa, G. L. Trevisan, D. Truong, F. Turco, A. D. Turnbull, E. A. Unterberg, P. Vaezi, P. J. Vail, M. A. Van Zeeland, M. Velasco Enriquez, M. C. Venkatesh, B. S. Victor, F. Volpe, M. R. Wade, M. L. Walker, J. R. Wall, G. M. Wallace, R. E. Waltz, G. Wang, H. Wang, Y. Wang, Z. Wang, F. Wang, S. H. Ward, J. G. Watkins, M. Watkins, W. P. Wehner, M. Weiland, D. B. Weisberg, A. S. Welander, A. E. White, R. B. White, D. Whyte, T. A. Wijkamp, R. Wilcox, T. Wilks, H. R. Wilson, A. Wingen, E. Wolfe, M. Wu, W. Wu, S. J. Wukitch, T. Xia, N. Xiang, B. Xiao, R. Xie, G. Xu, H. Xu, X. Xu, Z. Yan, Q. Yang, X. Yang, M. Yoshida, G. Yu, J. H. Yu, M. Yu, S. A. Zamperini, L. Zeng, B. Zhao, D. Zhao, H. Zhao, Y. Zhao, Y. Zhu, B. Zywicki, Abadie, L, Abrams, T, Ahn, J, Akiyama, T, Aleynikov, P, Allcock, J, Allen, E, Allen, S, Anderson, J, Ashourvan, A, Austin, M, Bak, J, Barada, K, Barbour, N, Bardoczi, L, Barr, J, Barton, J, Bass, E, Battaglia, D, Baylor, L, Beckers, J, Belli, E, Berkery, J, Bertelli, N, Bialek, J, Boedo, J, Boivin, R, Bonoli, P, Bortolon, A, Boyer, M, Brambila, R, Bray, B, Brennan, D, Briesemeister, A, Bringuier, S, Brookman, M, Brower, D, Brown, B, Brown, W, Buchenauer, D, Burke, M, Burrell, K, Butt, J, Buttery, R, Bykov, I, Candy, J, Canik, J, Cao, N, Carbajal Gomez, L, Carlson, L, Carlstrom, T, Carter, T, Cary, W, Casali, L, Cengher, M, Chan, V, Chen, B, Chen, J, Chen, M, Chen, R, Chen, X, Choi, W, Chrobak, C, Chrystal, C, Churchill, R, Cianciosa, M, Clauser, C, Clement, M, Coburn, J, Collins, C, Cooper, A, Covele, B, Crippen, J, Crocker, N, Crowley, B, Dal Molin, A, Davis, E, Degrassie, J, del-Castillo-Negrete, C, Delgado-Aparicio, L, Diallo, A, Diem, S, Ding, R, Ding, S, Ding, W, Doane, J, Donovan, D, Drake, J, Du, D, Du, H, Du, X, Duarte, V, Duran, J, Eidietis, N, Elder, D, Eldon, D, Elwasif, W, Ely, T, Eng, K, Engelhorn, K, Ennis, D, Erickson, K, Ernst, D, Evans, T, Fenstermacher, M, Ferraro, N, Ferron, J, Finkenthal, D, Fisher, P, Fishler, B, Flanagan, S, Fooks, J, Frassinetti, L, Frerichs, H, Fu, Y, Fulop, T, Gao, Q, Garcia, F, Garofalo, A, Gattuso, A, Giacomelli, L, Giraldez, E, Giroud, C, Glass, F, Gohil, P, Gong, X, Gorelov, Y, Granetz, R, Green, D, Greenfield, C, Grierson, B, Groebner, R, Grosnickle, W, Groth, M, Grunloh, H, Guo, H, Guo, W, Guterl, J, Hager, R, Hahn, S, Halpern, F, Han, H, Hansink, M, Hanson, J, Harris, J, Haskey, S, Hatch, D, Heidbrink, W, Herfindal, J, Hill, D, Hill, M, Hinson, E, Holcomb, C, Holland, C, Holland, L, Hollmann, E, Holm, A, Hong, R, Hoppe, M, Houshmandyar, S, Howard, J, Howard, N, Hu, Q, Hu, W, Huang, H, Huang, J, Huang, Y, Hughes, G, Hughes, J, Humphreys, D, Hyatt, A, Ida, K, Igochine, V, In, Y, Inoue, S, Isayama, A, Isler, R, Izzo, V, Jackson, M, Jarvinen, A, Jeon, Y, Ji, H, Jian, X, Jimenez, R, Johnson, C, Joseph, I, Kaczala, D, Kaplan, D, Kates-Harbeck, J, Kellman, A, Kellman, D, Kessel, C, Khumthong, K, Kim, C, Kim, H, Kim, J, Kim, K, Kim, S, Kimura, W, King, J, Kirk, A, Kleijwegt, K, Knolker, M, Kohn, A, Kolemen, E, Kostuk, M, Kramer, G, Kress, P, Kriete, D, La Haye, R, Laggner, F, Lan, H, Lanctot, M, Lantsov, R, Lao, L, Lasnier, C, Lau, C, Law, K, Lawrence, D, Le, J, Lee, R, Lehnen, M, Leon, R, Leonard, A, Lesher, M, Leuer, J, Li, G, Li, K, Liao, K, Lin, Z, Liu, C, Liu, F, Liu, Y, Liu, Z, Loch, S, Logan, N, Lohr, J, Lore, J, Luce, T, Luhmann, N, Lunsford, R, Luo, C, Luo, Z, Lupin-Jimenez, L, Lvovskiy, A, Lyons, B, Ma, X, Maingi, R, Makowski, M, Mantica, P, Manuel, M, Margo, M, Marinoni, A, Marmar, E, Martin, W, Masline, R, Matsunaga, G, Mauzey, D, Mauzey, P, Mcclenaghan, J, Mckee, G, Mclean, A, Mclean, H, Meier, E, Meitner, S, Menard, J, Meneghini, O, Merlo, G, Meyer, W, Miller, D, Miller, W, Moeller, C, Montes, K, Morales, M, Mordijck, S, Moser, A, Moyer, R, Muller, S, Munaretto, S, Murakami, M, Murphy, C, Muscatello, C, Myers, C, Nagy, A, Navratil, G, Nazikian, R, Neff, A, Neiser, T, Nelson, A, Nguyen, P, Nguyen, R, Nichols, J, Nocente, M, Nygren, R, O'Neill, R, Odstrcil, T, Ohdachi, S, Okabayashi, M, Olofsson, E, Ono, M, Orlov, D, Osborne, T, Pablant, N, Pace, D, Paguio, R, Pajares Martinez, A, Pan, C, Pankin, A, Park, J, Park, Y, Parker, C, Parker, S, Parks, P, Pawley, C, Paz-Soldan, C, Peebles, W, Penaflor, B, Petrie, T, Petty, C, Peysson, Y, Pigarov, A, Piglowski, D, Pinsker, R, Piovesan, P, Piper, N, Pitts, R, Pizzo, J, Podesta, M, Poli, F, Ponce, D, Porkolab, M, Porter, G, Prater, R, Qian, J, Ra, O, Rafiq, T, Raman, R, Rand, C, Randall, G, Rauch, J, Rea, C, Reinke, M, Ren, J, Ren, Q, Ren, Y, Rhodes, T, Rice, J, Rognlien, T, Rost, J, Rowan, W, Rudakov, D, Salmi, A, Sammuli, B, Samuell, C, Sandorfi, A, Sang, C, Sauter, O, Schissel, D, Schmitz, L, Schmitz, O, Schuster, E, Scoville, J, Seltzman, A, Sfiligoi, I, Shafer, M, Shen, H, Shi, T, Shiraki, D, Si, H, Smith, D, Smith, S, Snipes, J, Snyder, P, Solano, E, Solomon, W, Sontag, A, Soukhanovskii, V, Spong, D, Stacey, W, Staebler, G, Stagner, L, Stahl, B, Stangeby, P, Stoltzfus-Dueck, T, Stotler, D, Strait, E, Su, D, Sugiyama, L, Sulyman, A, Sun, Y, Sung, C, Suttrop, W, Suzuki, Y, Svyatkovskiy, A, Sweeney, R, Taimourzadeh, S, Takechi, M, Tala, T, Tan, H, Tang, S, Tang, X, Taussig, D, Taylor, G, Taylor, N, Taylor, T, Teklu, A, Thomas, D, Thomas, M, Thome, K, Thorman, A, Tinguely, R, Tobias, B, Tooker, J, Torreblanca, H, Torrezan De Sousa, A, Trevisan, G, Truong, D, Turco, F, Turnbull, A, Unterberg, E, Vaezi, P, Vail, P, Van Zeeland, M, Velasco Enriquez, M, Venkatesh, M, Victor, B, Volpe, F, Wade, M, Walker, M, Wall, J, Wallace, G, Waltz, R, Wang, G, Wang, H, Wang, Y, Wang, Z, Wang, F, Ward, S, Watkins, J, Watkins, M, Wehner, W, Weiland, M, Weisberg, D, Welander, A, White, A, White, R, Whyte, D, Wijkamp, T, Wilcox, R, Wilks, T, Wilson, H, Wingen, A, Wolfe, E, Wu, M, Wu, W, Wukitch, S, Xia, T, Xiang, N, Xiao, B, Xie, R, Xu, G, Xu, H, Xu, X, Yan, Z, Yang, Q, Yang, X, Yoshida, M, Yu, G, Yu, J, Yu, M, Zamperini, S, Zeng, L, Zhao, B, Zhao, D, Zhao, H, Zhao, Y, Zhu, Y, Zywicki, B, L. Abadie, T. W. Abrams, J. Ahn, T. Akiyama, P. Aleynikov, J. Allcock, E. O. Allen, S. Allen, J. P. Anderson, A. Ashourvan, M. E. Austin, J. Bak, K. K. Barada, N. Barbour, L. Bardoczi, J. Barr, J. L. Barton, E. M. Bass, D. Battaglia, L. R. Baylor, J. Beckers, E. A. Belli, J. W. Berkery, N. Bertelli, J. M. Bialek, J. A. Boedo, R. L. Boivin, P. T. Bonoli, A. Bortolon, M. D. Boyer, R. E. Brambila, B. Bray, D. P. Brennan, A. R. Briesemeister, S. A. Bringuier, M. W. Brookman, D. L. Brower, B. R. Brown, W. D. Brown, D. Buchenauer, M. G. Burke, K. H. Burrell, J. Butt, R. J. Buttery, I. Bykov, J. M. Candy, J. M. Canik, N. M. Cao, L. Carbajal Gomez, L. C. Carlson, T. N. Carlstrom, T. A. Carter, W. Cary, L. Casali, M. Cengher, V. S. Chan, B. Chen, J. Chen, M. Chen, R. Chen, Xi Chen, W. Choi, C. Chrobak, C. Chrystal, R. M. Churchill, M. Cianciosa, C. F. Clauser, M. Clement, J. Coburn, C. S. Collins, A. W. Cooper, B. M. Covele, J. W. Crippen, N. A. Crocker, B. J. Crowley, A. Dal Molin, E. M. Davis, J. S. deGrassie, C. A. del-Castillo-Negrete, L. F. Delgado-Aparicio, A. Diallo, S. J. Diem, R. Ding, S. Ding, W. Ding, J. L. Doane, D. C. Donovan, J. Drake, D. Du, H. Du, X. Du, V. Duarte, J. D. Duran, N. W. Eidietis, D. Elder, D. Eldon, W. Elwasif, T. E. Ely, K. M. Eng, K. Engelhorn, D. Ennis, K. Erickson, D. R. Ernst, T. E. Evans, M. E. Fenstermacher, N. M. Ferraro, J. R. Ferron, D. F. Finkenthal, P. A. Fisher, B. Fishler, S. M. Flanagan, J. A. Fooks, L. Frassinetti, H. G. Frerichs, Y. Fu, T. Fulop, Q. Gao, F. Garcia, A. M. Garofalo, A. Gattuso, L. Giacomelli, E. M. Giraldez, C. Giroud, F. Glass, P. Gohil, X. Gong, Y. A. Gorelov, R. S. Granetz, D. L. Green, C. M. Greenfield, B. A. Grierson, R. J. Groebner, W. H. Grosnickle, M. Groth, H. J. Grunloh, H. Y. Guo, W. Guo, J. Guterl, R. C. Hager, S. Hahn, F. D. Halpern, H. Han, M. J. Hansink, J. M. Hanson, J. Harris, S. R. Haskey, D. R. Hatch, W. W. Heidbrink, J. Herfindal, D. N. Hill, M. D. Hill, E. T. Hinson, C. T. Holcomb, C. G. Holland, L. D. Holland, E. M. Hollmann, A. M. Holm, R. Hong, M. Hoppe, S. Houshmandyar, J. Howard, N. T. Howard, Q. Hu, W. Hu, H. Huang, J. Huang, Y. Huang, G. A. Hughes, J. Hughes, D. A. Humphreys, A. W. Hyatt, K. Ida, V. Igochine, Y. In, S. Inoue, A. Isayama, R. C. Isler, V. A. Izzo, M. R. Jackson, A. E. Jarvinen, Y. Jeon, H. Ji, X. Jian, R. Jimenez, C. A. Johnson, I. Joseph, D. N. Kaczala, D. H. Kaplan, J. Kates-Harbeck, A. G. Kellman, D. H. Kellman, C. E. Kessel, K. Khumthong, C. C. Kim, H. Kim, J. Kim, K. Kim, S. H. Kim, W. Kimura, J. R. King, A. Kirk, K. Kleijwegt, M. Knolker, A. Kohn, E. Kolemen, M. Kostuk, G. J. Kramer, P. Kress, D. M. Kriete, R. J. La Haye, F. M. Laggner, H. Lan, M. J. Lanctot, R. Lantsov, L. L. Lao, C. J. Lasnier, C. Lau, K. Law, D. Lawrence, J. Le, R. L. Lee, M. Lehnen, R. Leon, A. W. Leonard, M. Lesher, J. A. Leuer, G. Li, K. Li, K. T. Liao, Z. Lin, C. Liu, F. Liu, Y. Liu, Z. Liu, S. Loch, N. C. Logan, J. M. Lohr, J. Lore, T. C. Luce, N. C. Luhmann, R. Lunsford, C. Luo, Z. Luo, L. Lupin-Jimenez, A. Lvovskiy, B. C. Lyons, X. Ma, R. Maingi, M. A. Makowski, P. Mantica, M. Manuel, M. W. Margo, A. Marinoni, E. Marmar, W. C. Martin, R. L. Masline, G. K. Matsunaga, D. M. Mauzey, P. S. Mauzey, J. T. Mcclenaghan, G. R. Mckee, A. G. Mclean, H. S. Mclean, E. Meier, S. J. Meitner, J. E. Menard, O. Meneghini, G. Merlo, W. H. Meyer, D. C. Miller, W. J. Miller, C. P. Moeller, K. J. Montes, M. A. Morales, S. Mordijck, A. Moser, R. A. Moyer, S. A. Muller, S. Munaretto, M. Murakami, C. J. Murphy, C. M. Muscatello, C. E. Myers, A. Nagy, G. A. Navratil, R. M. Nazikian, A. L. Neff, T. F. Neiser, A. Nelson, P. Nguyen, R. Nguyen, J. H. Nichols, M. Nocente, R. E. Nygren, R. C. O'Neill, T. Odstrcil, S. Ohdachi, M. Okabayashi, E. Olofsson, M. Ono, D. M. Orlov, T. H. Osborne, N. A. Pablant, D. C. Pace, R. R. Paguio, A. Pajares Martinez, C. Pan, A. Pankin, J. M. Park, J. Park, Y. Park, C. T. Parker, S. E. Parker, P. B. Parks, C. J. Pawley, C. A. Paz-Soldan, W. A. Peebles, B. G. Penaflor, T. W. Petrie, C. C. Petty, Y. Peysson, A. Y. Pigarov, D. A. Piglowski, R. I. Pinsker, P. Piovesan, N. Piper, R. A. Pitts, J. D. Pizzo, M. L. Podesta, F. M. Poli, D. Ponce, M. Porkolab, G. D. Porter, R. Prater, J. Qian, O. Ra, T. Rafiq, R. Raman, C. Rand, G. C. Randall, J. M. Rauch, C. Rea, M. L. Reinke, J. Ren, Q. Ren, Y. Ren, T. L. Rhodes, J. Rice, T. D. Rognlien, J. C. Rost, W. L. Rowan, D. L. Rudakov, A. Salmi, B. S. Sammuli, C. M. Samuell, A. M. Sandorfi, C. Sang, O. J. Sauter, D. P. Schissel, L. Schmitz, O. Schmitz, E. J. Schuster, J. T. Scoville, A. Seltzman, I. Sfiligoi, M. Shafer, H. Shen, T. Shi, D. Shiraki, H. Si, D. R. Smith, S. P. Smith, J. A. Snipes, P. B. Snyder, E. R. Solano, W. M. Solomon, A. C. Sontag, V. A. Soukhanovskii, D. A. Spong, W. M. Stacey, G. M. Staebler, L. Stagner, B. Stahl, P. C. Stangeby, T. J. Stoltzfus-Dueck, D. P. Stotler, E. J. Strait, D. Su, L. E. Sugiyama, A. A. Sulyman, Y. Sun, C. Sung, W. A. Suttrop, Y. Suzuki, A. Svyatkovskiy, R. M. Sweeney, S. Taimourzadeh, M. Takechi, T. Tala, H. Tan, S. Tang, X. Tang, D. Taussig, G. Taylor, N. Z. Taylor, T. S. Taylor, A. Teklu, D. M. Thomas, M. B. Thomas, K. E. Thome, A. R. Thorman, R. A. Tinguely, B. J. Tobias, J. F. Tooker, H. Torreblanca, A. Torrezan De Sousa, G. L. Trevisan, D. Truong, F. Turco, A. D. Turnbull, E. A. Unterberg, P. Vaezi, P. J. Vail, M. A. Van Zeeland, M. Velasco Enriquez, M. C. Venkatesh, B. S. Victor, F. Volpe, M. R. Wade, M. L. Walker, J. R. Wall, G. M. Wallace, R. E. Waltz, G. Wang, H. Wang, Y. Wang, Z. Wang, F. Wang, S. H. Ward, J. G. Watkins, M. Watkins, W. P. Wehner, M. Weiland, D. B. Weisberg, A. S. Welander, A. E. White, R. B. White, D. Whyte, T. A. Wijkamp, R. Wilcox, T. Wilks, H. R. Wilson, A. Wingen, E. Wolfe, M. Wu, W. Wu, S. J. Wukitch, T. Xia, N. Xiang, B. Xiao, R. Xie, G. Xu, H. Xu, X. Xu, Z. Yan, Q. Yang, X. Yang, M. Yoshida, G. Yu, J. H. Yu, M. Yu, S. A. Zamperini, L. Zeng, B. Zhao, D. Zhao, H. Zhao, Y. Zhao, Y. Zhu, and B. Zywicki

Abstract

DIII-D research is addressing critical challenges in preparation for ITER and the next generation of fusion devices through focusing on plasma physics fundamentals that underpin key fusion goals, understanding the interaction of disparate core and boundary plasma physics, and developing integrated scenarios for achieving high performance fusion regimes. Fundamental investigations into fusion energy science find that anomalous dissipation of runaway electrons (RE) that arise following a disruption is likely due to interactions with RE-driven kinetic instabilities, some of which have been directly observed, opening a new avenue for RE energy dissipation using naturally excited waves. Dimensionless parameter scaling of intrinsic rotation and gyrokinetic simulations give a predicted ITER rotation profile with significant turbulence stabilization. Coherence imaging spectroscopy confirms near sonic flow throughout the divertor towards the target, which may account for the convection-dominated parallel heat flux. Core-boundary integration studies show that the small angle slot divertor achieves detachment at lower density and extends plasma cooling across the divertor target plate, which is essential for controlling heat flux and erosion. The Super H-mode regime has been extended to high plasma current (2.0 MA) and density to achieve very high pedestal pressures (∼30 kPa) and stored energy (3.2 MJ) with H 98y2 ≈ 1.6-2.4. In scenario work, the ITER baseline Q = 10 scenario with zero injected torque is found to have a fusion gain metric independent of current between q 95 = 2.8-3.7, and a lower limit of pedestal rotation for RMP ELM suppression has been found. In the wide pedestal QH-mode regime that exhibits improved performance and no ELMs, the start-up counter torque has been eliminated so that the entire discharge uses ≈0 injected torque and the operating space is more ITER-relevant. Finally, the high- (3.8) hybrid scenario has been extended to the high-density levels ne

Published
2019

10. Overview of Innovative PMI Research on NSTX-U and Associated PMI Facilities at PPPL

Author

Rajesh Maingi, Filippo Scotti, V. A. Soukhanovskii, R. Kaita, M. Ono, C. N. Skinner, Michael Jaworski, and Jean Paul Allain

Subjects
010302 applied physics, Nuclear and High Energy Physics, Nuclear Energy and Engineering, Mechanical Engineering, Divertor, Nuclear engineering, 0103 physical sciences, Magnetic confinement fusion, General Materials Science, Auxiliary heating, 01 natural sciences, 010305 fluids & plasmas, Civil and Structural Engineering
Abstract

Developing a reactor compatible divertor and managing the associated plasma material interaction (PMI) has been identified as a high priority research area for magnetic confinement fusion. Accordingly on NSTX-U, the PMI research has received a strong emphasis. Moreover, with ˜15 MW of auxiliary heating power, NSTX-U will be able to test the PMI physics with the peak divertor plasma facing component (PFC) heat loads of up to 40-60 MW/m2.

Published
2013

11. Overview of physics results from MAST

Author

Choong-Seock Chang, Guoqin Yu, Guoyong Fu, Allen H. Boozer, Jong-Kyu Park, William Heidbrink, A. Bortolon, Stephen Jardin, S. Ethier, H.W. Kugel, Eugenio Schuster, Alexander Smirnov, Maxim Umansky, R. E. Bell, B. Stratton, David N. Ruzic, D.A. Humphreys, W. Davis, Calvin Domier, Nobuhiro Nishino, F. Jaeger, Brian Nelson, Y. Liang, C. Taylor, Ahmed Hassanein, Gennady V. Miloshevsky, David R. Smith, R. Nygren, W. X. Wang, J.R. Myra, D. S. Darrow, C.H. Skinner, Jean Paul Allain, J. Whaley, Leonid E. Zakharov, K.L. Wong, Mario Podesta, Robert Bastasz, Elena Belova, Roscoe White, Clarence Worth Rowley, H. Takahashi, P.T. Bonoli, T.S. Bigelow, William Dorland, Tobin Munsat, Masayuki Ono, Sergei Krasheninnikov, J. C. Hosea, Dennis L. Youchison, Z. Xia, E. Ruskov, S. S. Medley, J.R. Ferron, D. Russell, Ahmed Diallo, Richard Majeski, S. Ding, D.C. McCune, D. Zemlyanov, P. B. Snyder, Todd Evans, J.M. Bialek, H. F. Meyer, G. Taylor, T.K. Gray, G. Zimmer, O. Katsuro-Hopkins, B.P. LeBlanc, John Wright, M.G. Bell, J.A. Boedo, D. Mueller, William R. Wampler, M.J. Schaffer, D. J. Battaglia, D. Liu, R. J. Buttery, Aaron Sontag, Robert Kaita, Stanley Kaye, S. Kubota, Manfred Bitter, P. W. Ross, S.F. Paul, L. F. Delgado-Aparicio, Fred Levinton, G. Caravelli, Peter Beiersdorfer, Stewart Zweben, Yoshiki Hirooka, George McKee, Hyeon K. Park, B.G. Penaflor, G. Rewoldt, Dan Stutman, W. M. Solomon, Michael Jaworski, Thomas Jarboe, Yuichi Takase, Dylan Brennan, S.P. Gerhardt, John Berkery, J. Breslau, A. Pigarov, Jonathan Menard, John B Wilgen, T.S. Hahm, D.K. Mansfield, K. C. Lee, T.H. Osborne, T. Stoltzfus-Dueck, E. B. Hooper, Adam McLean, K. Indireshkumar, Xian-Zhu Tang, R. W. Harvey, C. K. Phillips, Naoki Tamura, J. Manickam, Neal Crocker, H. Yuh, R. Frazin, J. Kallman, D. Tsarouhas, Michael Finkenthal, R.J. Maqueda, Alan H. Glasser, R. Andre, Nikolai Gorelenkov, K. W. Hill, B. Hu, W. A. Peebles, B. McGeehan, H. Reimerdes, Valeryi Sizyuk, Jakub Urban, L.L. Lao, Kouji Shinohara, Chase N. Taylor, R. Wilson, R.J. La Haye, C.E. Kessel, Woochang Lee, S.A. Sabbagh, Joon-Wook Ahn, D. R. Mikkelsen, P.M. Ryan, Riccardo Betti, M. Menon, Vladimir Shevchenko, J. Kim, Kevin Tritz, Josef Preinhaelter, Y. Guo, E. Mazzucato, W. Guttenfelder, M.L. Walker, D.P. Stotler, Roger Raman, Rajesh Maingi, Filippo Scotti, V. A. Soukhanovskii, John Canik, D. A. D'Ippolito, R.J. Fonck, E.D. Fredrickson, Ker-Chung Shaing, J. Foley, Y. Ren, David Gates, Egemen Kolemen, Neville C. Luhmann, J.A. Leuer, and Science and Technology of Nuclear Fusion

Subjects
Physics, Nuclear and High Energy Physics, Mega Ampere Spherical Tokamak, Tokamak, Divertor, Magnetic confinement fusion, Plasma, Collisionality, Spherical tokamak, Condensed Matter Physics, Resonant magnetic perturbations, Computational physics, law.invention, Physics::Plasma Physics, law, Atomic physics
Abstract

Major developments on the Mega Amp Spherical Tokamak (MAST) have enabled important advances in support of ITER and the physics basis of a spherical tokamak (ST) based component test facility (CTF), as well as providing new insight into underlying tokamak physics. For example, L–H transition studies benefit from high spatial and temporal resolution measurements of pedestal profile evolution (temperature, density and radial electric field) and in support of pedestal stability studies the edge current density profile has been inferred from motional Stark effect measurements. The influence of the q-profile and E × B flow shear on transport has been studied in MAST and equilibrium flow shear has been included in gyro-kinetic codes, improving comparisons with the experimental data. H-modes exhibit a weaker q and stronger collisionality dependence of heat diffusivity than implied by IPB98(y,2) scaling, which may have important implications for the design of an ST-based CTF. ELM mitigation, an important issue for ITER, has been demonstrated by applying resonant magnetic perturbations (RMPs) using both internal and external coils, but full stabilization of type-I ELMs has not been observed. Modelling shows the importance of including the plasma response to the RMP fields. MAST plasmas with q > 1 and weak central magnetic shear regularly exhibit a long-lived saturated ideal internal mode. Measured plasma braking in the presence of this mode compares well with neo-classical toroidal viscosity theory. In support of basic physics understanding, high resolution Thomson scattering measurements are providing new insight into sawtooth crash dynamics and neo-classical tearing mode critical island widths. Retarding field analyser measurements show elevated ion temperatures in the scrape-off layer of L-mode plasmas and, in the presence of type-I ELMs, ions with energy greater than 500 eV are detected 20 cm outside the separatrix. Disruption mitigation by massive gas injection has reduced divertor heat loads by up to 70%.

Published
2011

12. Simulations of NSTX with a Liquid Lithium Divertor Module

Author

H.W. Kugel, Leonid E. Zakharov, D.P. Stotler, T.D. Rognlien, Rajesh Maingi, V. A. Soukhanovskii, and A. Yu. Pigarov

Subjects
Materials science, Tokamak, Nuclear engineering, Divertor, chemistry.chemical_element, Plasma, Condensed Matter Physics, law.invention, chemistry, Heat flux, law, Heat transfer, Diagnostic data, Lithium, Atomic physics, Liquid lithium
Abstract

A strategy to develop self-consistent simulations of the behavior of lithium in the Liquid Lithium Divertor (LLD) module to be installed in NSTX is described. In this initial stage of the plan, the UEDGE edge plasma transport code is used to simulate an existing NSTX shot, with UEDGE's transport coefficients set using midplane and divertor diagnostic data. The LLD is incorporated into the simulations as a reduction in the recycling coefficient over the outer divertor. Heat transfer calculations performed using the resulting heat flux profiles provide preliminary estimates on operating limits for the LLD as well as input data for subsequent steps in the LLD modeling effort.

Published
2010

13. Recent results from the National Spherical Torus Experiment

Author

R Maingi, M G Bell, R E Bell, J Bialek, C Bourdelle, C E Bush, D S Darrow, E D Fredrickson, D A Gates, M Gilmore, T Gray, T R Jarboe, D W Johnson, R Kaita, S M Kaye, S Kubota, H W Kugel, B P LeBlanc, R J Maqueda, D Mastrovito, S S Medley, J E Menard, D Mueller, B A Nelson, M Ono, F Paoletti, H K Park, S F Paul, T Peebles, Y-K M Peng, C K Phillips, R Raman, A L Rosenberg, A L Roquemore, P M Ryan, S A Sabbagh, C H Skinner, V A Soukhanovskii, D Stutman, D W Swain, E J Synakowski, G Taylor, J Wilgen, J R Wilson, G A Wurden, S J Zweben, and the NSTX Team

Subjects
Physics, Tokamak, Divertor, Nuclear engineering, Magnetic confinement fusion, Torus, Condensed Matter Physics, Helicity, law.invention, Nuclear physics, Nuclear Energy and Engineering, Heat flux, law, Current (fluid), Coaxial
Abstract

The National Spherical Torus Experiment (NSTX) is a low aspect-ratio fusion research facility whose research goal is to make a determination of the attractiveness of the spherical torus concept in the areas of high-β stability, confinement, current drive, and divertor physics. Remarkable progress was made in extending the operational regime of the device in FY 2002. In brief, βt of 34% and βN of 6.5 were achieved. H-mode became the main operational regime, and energy confinement exceeded conventional aspect-ratio tokamak scalings. Heating was demonstrated with the radiofrequency antenna, and signatures of current drive were observed. Current initiation with coaxial helicity injection produced discharges of 400 kA, and first measurements of divertor heat flux profiles in H-mode were made.

Published
2003

14. Initial studies of core and edge transport of NSTX plasmas

Author

E J Synakowski, M G Bell, R E Bell, C E Bush, C Bourdelle, D Darrow, W Dorland, A Ejiri, E D Fredrickson, D A Gates, S M Kaye, S Kubota, H W Kugel, B P LeBlanc, R Maingi, R J Maqueda, J E Menard, D Mueller, A Rosenberg, S A Sabbagh, D Stutman, G Taylor, D W Johnson, R Kaita, M Ono, F Paoletti, W Peebles, Y-K M Peng, A L Roquemore, C H Skinner, V A Soukhanovskii, and the NSTX Research Team

Subjects
Physics, Nuclear Energy and Engineering, Physics::Plasma Physics, Magnetic confinement fusion, Electron temperature, Plasma diagnostics, Plasma, Electron, Atomic physics, Condensed Matter Physics, Thermal conduction, Neutral beam injection, Ion
Abstract

Rapidly developing diagnostic, operational, and analysis capability is enabling the first detailed local physics studies to begin in high β plasmas of the National Spherical Torus Experiment (NSTX). These studies are motivated in part by the observation of energy confinement times in neutral-beam-heated discharges that are favourable with respect to predictions from the ITER-89P scaling expression. For plasmas heated with neutral beam injection (NBI), analysis based on profile measurements suggests that electron heat conduction is the dominant thermal loss channel. Cases where early analysis indicates that ion thermal conduction may be exceptionally low is motivating studies of possible sources of ion heating not presently accounted for by classical collisional processes. Gyrokinetic microstability studies indicate that long wavelength turbulence with kθρi~0.1-1 may be stable or suppressed by E×B shear in these plasmas, while modes with kθρi~50 may be robust. High harmonic fast wave (HHFW) heating efficiently heats electrons on NSTX, and studies have begun using it to assess transport in the electron channel. Regarding edge transport, H-mode transitions occur with either NBI or HHFW heating. The power required for L- to H-mode transitions far exceeds that expected from empirical ELM-free H-mode scaling laws derived from moderate aspect ratio devices. Finally, initial fluctuation measurements made with two techniques are permitting the first characterizations of edge turbulence.

Published
2002

15. PPPS-2013: Modeling snowflake divertors for reduced surface heat-flux in tokamaks

Author

Maxim Umansky, V. A. Soukhanovskii, S. A. Allen, D. D. Ryutov, Ronald H. Cohen, and T.D. Rognlien

Subjects
Physics, Tokamak, Heat flux, law, Divertor, Magnetic pressure, Mechanics, Plasma, Atomic physics, Snowflake, Plasma stability, Magnetic flux, law.invention
Abstract

Summary form only given. The high peak heat-flux of plasma exhaust in magnetic fusion devices incident on material surfaces could exceed material limits and must be controlled. The magnetic snowflake divertor1 can alleviate this problem by introducing a null in the poloidal magnetic field, Bp, where Bp's local strength varies as the square of the distance from the null compared to the linear variation of the standard X-point divertor. The increased magnetic flux expansion of the snowflake and the high ratio of plasma-to-poloidal magnetic pressure, termed βp, are predicted to reduce both steady state heat flux and that from large, intermittent edge localized modes (ELMs).1,2 Experiments in TCV (Lausanne), NSTX (Princeton Plasma Physics Lab), and DIII-D (General Atomics) tokamaks have observed substantial heat-flux reduction when using a snowflake configuration. Some of these effects have been modeled by the 2D UEDGE edge plasma/neutral transport code.3 Here we present extensions to that modeling to include detailed comparison with the new experimental results from DIII-D.4 In addition, we add a feedback model such that the radial spreading of the ELM by plasma convection2 near the null point is proportional to the local βp, thus providing a dynamic description of the spreading during the ELM.

Published
2013

16. Overview of Innovative PMI Research on NSTX-U and Associated PMI Facilities at PPPL

Author

Jean Paul Allain, C. N. Skinner, R. Kaita, M. Ono, Michael Jaworski, Rajesh Maingi, Filippo Scotti, and V. A. Soukhanovskii

Subjects
Physics, chemistry, Heat flux, Divertor, Nuclear engineering, chemistry.chemical_element, Mechanical engineering, Flux, Lithium Tokamak Experiment, Magnetic confinement fusion, Lithium, Plasma, Diagnostic tools
Abstract

Developing a reactor compatible divertor and managing the associated plasma material interaction (PMI) has been identified as a high priority research area for magnetic confinement fusion. Accordingly on NSTXU, the PMI research has received a strong emphasis. With ~ 15 MW of auxiliary heating power, NSTX-U will be able to test the PMI physics with the peak divertor plasma facing component (PFC) heat loads of up to 40-60 MW/m2 . To support the PMI research, a comprehensive set of PMI diagnostic tools are being implemented. The snow-flake configuration can produce exceptionally high divertor flux expansion of up to ~ 50. Combined with the radiative divertor concept, the snow-flake configuration has reduced the divertor heat flux by an order of magnitude in NSTX. Another area of active PMI investigation is the effect of divertor lithium coating (both in solid and liquid phases). The overall NSTX lithium PFC coating results suggest exciting opportunities for future magnetic confinement research including significant electron energy confinement improvements, Hmode power threshold reduction, the control of Edge Localized Modes (ELMs), and high heat flux handling. To support the NSTX-U/PPPL PMI research, there are also a number of associated PMI facilities implemented at PPPL/Princeton University including the Liquid Lithium R&D facility, Lithium Tokamak Experiment, and Laboratories for Materials Characterization and Surface Chemistry.

Published
2012

17. NSTX Report on FES Joint Facilities Research Milestone 2010

Author

J W. Ahn, V A Soukhanovskii, R. Maingi, T. K. Gray, and A. G. McLean

Subjects
Tokamak, Thermal transport, Heat flux, law, Chemistry, Beta (plasma physics), Divertor, Nuclear engineering, Mechanical engineering, Plasma, Collisionality, Joint (geology), law.invention
Abstract

Annual Target: Conduct experiments on major fusion facilities to improve understanding of the heat transport in the tokamak scrape-off layer (SOL) plasma, strengthening the basis for projecting divertor conditions in ITER. The divertor heat flux profiles and plasma characteristics in the tokamak scrape-off layer will be measured in multiple devices to investigate the underlying thermal transport processes. The unique characteristics of C-Mod, DIII-D, and NSTX will enable collection of data over a broad range of SOL and divertor parameters (e.g., collisionality ν*, beta β, parallel heat flux q||, and divertor geometry). Coordinated experiments using common analysis methods will generate a data set that will be compared with theory and simulation.

Published
2011

20. Edge Recycling and Heat Fluxes in L- and H-mode NSTX Plasmas

Author

A.L. Roquemore, B. LeBlanc, C.J. Lasnier, V. A. Soukhanovskii, H. K. Kugel, R. Maingi, and Roger Raman

Subjects
Nuclear physics, Electron density, Chemistry, Divertor, Nuclear engineering, Mode (statistics), Particle, Plasma, Edge (geometry), Scaling
Abstract

Introduction Edge characterization experiments have been conducted in NSTX to provide an initial survey of the edge particle and heat fluxes and their scaling with input power and electron density. The experiments also provided a database of conditions for the analyses of the NSTX global particle sources, core fueling, and divertor operating regimes.

Published
2003

21. Disruptions, disruptivity and safer operating windows in the high-βspherical torus NSTX

Author

R.E. Bell, Kevin Tritz, Howard Yuh, David Gates, V. A. Soukhanovskii, Jonathan Menard, B.P. LeBlanc, S.P. Gerhardt, D. Mueller, S.A. Sabbagh, and Ahmed Diallo

Subjects
Physics, Nuclear and High Energy Physics, Tokamak, Torus, Mechanics, Current ramp, Spherical tokamak, Condensed Matter Physics, Rotation, Plasma current, law.invention, law, High current, Atomic physics, National Spherical Torus Experiment
Abstract

This paper discusses disruption rates, disruption causes and disruptivity statistics in the high-βN National Spherical Torus Experiment (NSTX) (Ono et al 2000 Nucl. Fusion 40 557). While the overall disruption rate is rather high, configurations with high βN, moderate q*, strong boundary shaping, sufficient rotation and broad pressure and current profiles are found to have the lowest disruptivity; active n = 1 control further reduces the disruptivity. The disruptivity increases rapidly for q* 1.25 is generally acceptable for avoiding the onset of core rotating n = 1 kink/tearing modes; when EPM and ELM disturbances are present, the required qmin for avoiding those modes is raised to ∼1.5. The current ramp and early flat-top phase of the discharges are prone to n = 1 core rotating modes locking to the wall, leading to a disruption. Small changes to the discharge fuelling during this phase can often mitigate the rotation damping associated with these modes and eliminate the disruption. The largest stored-energy disruptions are those that occur at high current when a plasma current ramp-down is initiated incorrectly.

Published
2013

23. Observation of He-like Satellite Lines of the H-like Potassium K xix Emission.

Author

M. E. Weller, P. Beiersdorfer, T. E. Lockard, G. V. Brown, A. McKelvey, J. Nilsen, R. Shepherd, V. A. Soukhanovskii, M. P. Hill, L. M. R. Hobbs, D. Burridge, D. J. Hoarty, J. Morton, L. Wilson, S. J. Rose, and P. Hatfield

Subjects
ION recombination, ARTIFICIAL satellites, ELECTRON temperature, DARK matter, POTASSIUM, X-ray spectrometers, GALAXY clusters
Abstract

We present measurements of the H-like potassium (K xix) X-ray spectrum and its He-like (K xviii) satellite lines, which are situated in the wavelength region between 3.34 and 3.39 Å, which has been of interest for the detection of dark matter. The measurements were taken with a high-resolution X-ray spectrometer from targets irradiated by a long-pulse (2 ns) beam from the Orion laser facility. We obtain experimental wavelength values of dielectronic recombination satellite lines and show that the ratio of the Lyα lines and their dielectronic satellite lines can be used to estimate the electron temperature, which in our case was about 1.5 ± 0.3 keV. [ABSTRACT FROM AUTHOR]

Published
2019
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24. Electron-density-sensitive Line Ratios of Fe xiii– xvi from Laboratory Sources Compared to CHIANTI.

Author

M. E. Weller, P. Beiersdorfer, V. A. Soukhanovskii, F. Scotti, and B. P. LeBlanc

Subjects
ELECTRON density, IRON alloys, WAVELENGTHS, ASTROPHYSICS, THOMSON scattering
Abstract

We present electron-density-sensitive line ratios for Fe xiii– xvi measured in the spectral wavelength range of 200–440 Å and an electron density range of (1–4) × 1013 cm−3. The results provide a test at the high-density limit of density-sensitive line ratios useful for astrophysical studies. The measurements were performed on the National Spherical Torus Experiment-Upgrade, where electron densities were measured independently by the laser Thomson scattering diagnostic. Spectra were collected with a flat-field grazing-incidence spectrometer, which provided a spectral resolution of up to 0.3 Å, i.e., high resolution across the broad wavelength range. The response of the instrument was relatively calibrated using spectroscopic techniques in order to improve accuracy. The line ratios are compared to other laboratory sources and the latest version of CHIANTI (8.0.2), and an agreement within 30% is found. [ABSTRACT FROM AUTHOR]

Published
2018
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25. Effect of 3D magnetic perturbations on divertor conditions and detachment in tokamak and stellarator.

Author

J-W Ahn, A R Briesemester, M Kobayashi, J D Lore, O Schmitz, A Diallo, T K Gray, C J Lasnier, B P LeBlanc, R Maingi, A G McLean, S A Sabbagh, and V A Soukhanovskii

Subjects
TOKAMAKS, STELLARATORS, FUSION reactor divertors, PERTURBATION theory, FLUID flow
Abstract

Enhanced perpendicular heat and momentum transport induces parallel pressure loss leading to divertor detachment, which can be produced by the increase of density in 2D tokamaks. However, in the 3D configurations such as tokamaks with 3D fields and stellarators, the fraction of perpendicular transport can be higher even in a lower density regime, which could lead to the early transition to detachment without passing through the high-recycling regime. 3D fields applied to the limiter tokamak plasmas produce edge stochastic layers close to the last closed flux surface (LCFS), which can allow for enhanced perpendicular transport and indeed the absence of high recycling regime and early detachment have been observed in TEXTOR and Tore Supra. However, in the X-point divertor tokamaks with the applied 3D fields, the parallel transport is still dominant and the detachment facilitation has not been observed yet. Rather, 3D fields affected detachment adversely under certain conditions, either by preventing detachment onset as seen in DIII-D or by re-attaching the existing detached plasma as shown in NSTX. The possible way for strong 3D effects to induce access to the early detachment in divertor tokamaks appears to be via significant perpendicular loss of parallel momentum by frictional force for the counter-streaming flows between neighboring flow channels in the divertor. In principle, the adjacent lobes in the 3D divertor tokamak may generate the counter-streaming flow channels. However, an EMC3-EIRENE simulation for ITER H-mode plasmas demonstrated that screened RMP leads to significantly reduced counter-flows near the divertor target, therefore the momentum loss effect leading to detachment facilitation is expected to be small. This is consistent with the observation in LHD, which showed screening (amplification) of RMP fields in the attachment (stable detachment) case. Work for optimal parameter window for best divertor operation scenario is needed particularly for the 3D divertor tokamak configuration. [ABSTRACT FROM AUTHOR]

Published
2017
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26. A review of radiative detachment studies in tokamak advanced magnetic divertor configurations.

Author

V A Soukhanovskii

Subjects
*TOKAMAKS, *DIVERTERS (Electronics), *POLOIDAL magnetic fields, *PLASMA materials processing, *HEAT losses
Abstract

The present vision for a plasma–material interface in the tokamak is an axisymmetric poloidal magnetic X-point divertor. Four tasks are accomplished by the standard poloidal X-point divertor: plasma power exhaust; particle control (D/T and He pumping); reduction of impurity production (source); and impurity screening by the divertor scrape-off layer. A low-temperature, low heat flux divertor operating regime called radiative detachment is viewed as the main option that addresses these tasks for present and future tokamaks. Advanced magnetic divertor configuration has the capability to modify divertor parallel and cross-field transport, radiative and dissipative losses, and detachment front stability. Advanced magnetic divertor configurations are divided into four categories based on their salient qualitative features: (1) multiple standard X-point divertors; (2) divertors with higher order nulls; (3) divertors with multiple X-points; and (4) long poloidal leg divertors (and also with multiple X-points). This paper reviews experiments and modeling in the area of radiative detachment in the advanced magnetic divertor configurations. [ABSTRACT FROM AUTHOR]

Published
2017
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