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1. Relative Afterslip Moment Does Not Correlate With Aftershock Productivity:Implications for the Relationship Between Afterslip and Aftershocks

Author

R. M. Churchill, M. J. Werner, J. Biggs, and Å. Fagereng

Subjects
Geophysics, General Earth and Planetary Sciences
Abstract

Aseismic afterslip has been proposed to drive aftershock sequences. Both afterslip moment and aftershock number broadly increase with mainshock size, but can vary beyond this scaling. We examine whether relative afterslip moment (afterslip moment/mainshock moment) correlates with several key aftershock sequence characteristics, including aftershock number and cumulative moment (both absolute and relative to mainshock size), seismicity rate change, b-value, and Omori decay exponent. We select Mw ≥ 4.5 aftershocks for 41 tectonically varied mainshocks with available afterslip models. Against expectation, relative afterslip moment does not correlate with tested aftershock characteristics or background seismicity rate. Furthermore, adding afterslip moment to mainshock moment does not improve predictions of aftershock number. Our findings place useful empirical constraints on the link between afterslip and potentially damaging Mw ≥ 4.5 aftershocks and raise questions regarding the role afterslip plays in aftershock generation.

Published
2022
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2. Electromagnetic total-f algorithm for gyrokinetic particle-in-cell simulations of boundary plasma in XGC

Author

Robert Hager, S. Ku, A. Y. Sharma, C. S. Chang, R. M. Churchill, and A. Scheinberg

Subjects
Condensed Matter Physics
Abstract

The simplified δf mixed-variable/pullback electromagnetic simulation algorithm implemented in XGC for core plasma simulations by Cole et al. [Phys. Plasmas 28, 034501 (2021)] has been generalized to a total- f electromagnetic algorithm that can include, for the first time, the boundary plasma in diverted magnetic geometry with neutral particle recycling, turbulence, and neoclassical physics. The δf mixed-variable/pullback electromagnetic implementation is based on the pioneering work by Kleiber and Mischenko et al. [Kleiber et al., Phys. Plasmas 23, 032501 (2016); Mishchenko et al., Comput. Phys. Commun. 238, 194 (2019)]. An electromagnetic demonstration simulation is performed in a DIII-D-like, H-mode boundary plasma, including a corresponding comparative electrostatic simulation, which confirms that the electromagnetic simulation is necessary for a higher fidelity understanding of the electron particle and heat transport even at the low- β pedestal foot in the vicinity of the magnetic separatrix.

Published
2022
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3. Normalizing flows for likelihood-free inference with fusion simulations

Author

C S Furia and R M Churchill

Subjects
Nuclear Energy and Engineering, Condensed Matter Physics
Abstract

Fluid-based scrape-off layer transport codes, such as UEDGE, are heavily utilized in tokamak analysis and design, but typically require user-specified anomalous transport coefficients to match experiments. Determining the uniqueness of these parameters and the uncertainties in them to match experiments can provide valuable insights to fusion scientists. We leverage recent work in the area of likelihood-free inference (‘simulation-based inference’) to train a neural network, which enables accurate statistical inference of the anomalous transport coefficients given experimental plasma profile input. UEDGE is treated as a black-box simulator and runs multiple times with anomalous transport coefficients sampled from priors, and the neural network is trained on these simulations to emulate the posterior. The neural network is trained as a normalizing flow model for density estimation, allowing it to accurately represent complicated, high-dimensional distribution functions. With a fixed simulation budget, we compare a single-round procedure to a multi-round approach that guides the training simulations toward a specific target observation. We discuss the future possibilities for use of amortized models, which train on a wide range of simulations and enable fast statistical inference for results during experiments.

Published
2022
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4. Near real-time streaming analysis of big fusion data

Author

R Kube, R M Churchill, C S Chang, J Choi, R Wang, S Klasky, L Stephey, E Dart, and M J Choi

Subjects
streaming analysis, Fluids & Plasmas, Molecular, FOS: Physical sciences, Condensed Matter Physics, Atomic, Physics - Plasma Physics, fusion energy, Other Physical Sciences, Plasma Physics (physics.plasm-ph), machine learning, Particle and Plasma Physics, Nuclear Energy and Engineering, Networking and Information Technology R&D (NITRD), big data, Physics - Data Analysis, Statistics and Probability, Nuclear, Data Analysis, Statistics and Probability (physics.data-an)
Abstract

Experiments on fusion plasmas produce high-dimensional data time series with ever-increasing magnitude and velocity, but turn-around times for analysis of this data have not kept up. For example, many data analysis tasks are often performed in a manual, ad-hoc manner some time after an experiment. In this article, we introduce the Delta framework that facilitates near real-time streaming analysis of big and fast fusion data. By streaming measurement data from fusion experiments to a high-performance compute center, Delta allows computationally expensive data analysis tasks to be performed in between plasma pulses. This article describes the modular and expandable software architecture of Delta and presents performance benchmarks of individual components as well as of an example workflow. Focusing on a streaming analysis workflow where electron cyclotron emission imaging (ECEi) data is measured at KSTAR on the National Energy Research Scientific Computing Center’s (NERSC’s) supercomputer we routinely observe data transfer rates of about 4 Gigabit per second. In NERSC, a demanding turbulence analysis workflow effectively utilizes multiple nodes and graphical processing units and executes them in under 5 min. We further discuss how Delta uses modern database systems and container orchestration services to provide web-based real-time data visualization. For the case of ECEi data we demonstrate how data visualizations can be augmented with outputs from machine learning models. By providing session leaders and physics operators, results of higher-order data analysis using live visualizations may make more informed decisions on how to configure the machine for the next shot.

Published
2021
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5. 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
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6. 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

8. Pedestal and edge electrostatic turbulence characteristics from an XGC1 gyrokinetic simulation.

Author

R M Churchill, C S Chang, S Ku, and J Dominski

Subjects
*ELECTROSTATICS, *TURBULENCE, *COLLISIONS (Physics), *H-mode plasma confinement, *ELECTRON density, *SIMULATION methods & models
Abstract

Understanding the multi-scale neoclassical and turbulence physics in the edge region (pedestal + scrape-off layer (SOL)) is required in order to reliably predict performance in future fusion devices. We explore turbulent characteristics in the edge region from a multi-scale neoclassical and turbulent XGC1 gyrokinetic simulation in a DIII-D like tokamak geometry, here excluding neutrals and collisions. For an H-mode type plasma with steep pedestal, it is found that the electron density fluctuations increase towards the separatrix, and stay high well into the SOL, reaching a maximum value of . Blobs are observed, born around the magnetic separatrix surface and propagate radially outward with velocities generally less than 1 km s−1. Strong poloidal motion of the blobs is also present, near 20 km s−1, consistent with E × B rotation. The electron density fluctuations show a negative skewness in the closed field-line pedestal region, consistent with the presence of ‘holes’, followed by a transition to strong positive skewness across the separatrix and into the SOL. These simulations indicate that not only neoclassical phenomena, but also turbulence, including the blob-generation mechanism, can remain important in the steep H-mode pedestal and SOL. Qualitative comparisons will be made to experimental observations. [ABSTRACT FROM AUTHOR]

Published
2017
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9. Synthetic diagnostic for the beam emission spectroscopy diagnostic using a full optical integration.

Author

L Hausammann, R M Churchill, and L Shi

Subjects
*SPECTRUM analysis, *ELECTRON density, *PLASMA gases, *TURBULENCE, *TOKAMAKS
Abstract

The beam emission spectroscopy (BES) diagnostic is used to measure fluctuations of electron density in the edge and core of fusion plasmas, and is a key in understanding turbulence in a plasma reactor. A synthetic BES diagnostic for the turbulence simulation code XGC1 has been developed using a realistic neutral beam model and an optical system easily adaptable to different kinds of tokamaks. The beam is modeled using multiple beam energy components, each one with a fraction of the total energy and their own mass and energy (mono-energetic components). The optical system consists of a lens focusing a bundle of optical fibers and resulting in a 2D measurement. The synthetic diagnostic gives similar correlation functions and behaviour of the turbulences than the usual methods that do not take into account the full 3D optical effects. The results, based on a simulation of XGC1, contain an analysis of the correlation (in space and time), a comparison of different approximations possible and their importance in accurately modeling the BES diagnostic. [ABSTRACT FROM AUTHOR]

Published
2017
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10. Radial localization of edge modes in Alcator C-Mod pedestals using optical diagnostics.

Author

C Theiler, J L Terry, E Edlund, I Cziegler, R M Churchill, J W Hughes, B LaBombard, T Golfinopoulos, and Team, the Alcator C-Mod

Subjects
CYCLOTRON resonance, PLASMA gases, CHARGE exchange, ELECTRIC fields, ACOUSTIC models
Abstract

Dedicated experiments in ion cyclotron range heated enhanced D-alpha (EDA) H-mode and I-mode plasmas have been performed on Alcator C-Mod to identify the location of edge fluctuations inside the pedestal and to determine their plasma frame phase velocity. For this purpose, measurements from gas puff imaging (GPI) and gas puff charge exchange recombination spectroscopy (GP-CXRS) have been collected using the same optical views. The data suggest that the EDA H-mode-specific quasi-coherent mode (QCM) is centered near the radial electric field (Er) well minimum and propagates along the ion diamagnetic drift direction in the plasma frame. The weakly coherent mode (WCM) and the geodesic acoustic mode observed in I-mode, on the other hand, are found to be located around the outer shear layer of the Er well. This results in a weak plasma frame phase velocity mostly along the electron diamagnetic drift direction for the WCM. The findings in these EDA H-mode plasmas differ from probe measurements in ohmic EDA H-mode (LaBombard et al 2014 Phys. Plasmas21 056108), where the QCM was identified as an electron drift-wave located several mm outside the Er well minimum in a region of positive Er. To explore if instrumental effects of the optical diagnostics could be the cause of the difference, a synthetic diagnostic for GPI is introduced. This diagnostic reproduces amplitude ratios and relative radial shifts of the mode profiles determined from poloidally and toroidally oriented optics and, if instrumental effects related to GP-CXRS are also included, indicates that the measured location of the QCM and WCM relative to the Er well reported here is only weakly affected by instrumental effects. [ABSTRACT FROM AUTHOR]

Published
2017
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