Publications

2020

  • R. Hager, C. Chang, N. Ferraro, and R. Nazikian. Gyrokinetic understanding of the edge pedestal transport driven by resonant magnetic perturbations in a realistic divertor geometry. Physics of Plasmas 27, 062301 (2020)

  • B. J. Sturdevant, S. E. Parker, C. S. Chang, and R. Hager. Verification of an improved equation-free projective integration method for neoclassical plasma-profile evolution in tokamak geometry. Physics of Plasmas 27, 032505 (2020)https://dx.doi.org/10.1063/1.5141337

  • D. Faghihi, V. Carey, C. Michoski, R. Hager, S. Janhunen, et al. Moment preserving constrained resampling with applications to particle-in-cell methods. Journal of Computational Physics 409, 109317 (2020)

  • M. D. J. Cole, T. Moritaka, R. Hager, J. Dominski, S. Ku, et al. Nonlinear global gyrokinetic delta-f turbulence simulations in a quasi-axisymmetric stellarator. Physics of Plasmas 27, 044501 (2020)

2019

  • J. Dominski, C. S. Chang, R. Hager, P. Helander, S. Ku, et al. Study of up-down poloidal density asymmetry of high- impurities with the new impurity version of XGCa. Journal of Plasma Physics 85, 905850510 (2019)

  • M. D. J. Cole, R. Hager, T. Moritaka, S. Lazerson, R. Kleiber, et al. Comparative collisionless alpha particle confinement in stellarator reactors with the XGC gyrokinetic code. Physics of Plasmas 26, 032506 (2019)

  • M. D. J. Cole, R. Hager, T. Moritaka, J. Dominski, R. Kleiber, et al. Verification of the global gyrokinetic stellarator code XGC-S for linear ion temperature gradient driven modes. Physics of Plasmas 26, 082501 (2019)

  • R. Churchill, C. S. Chang, S. Ku, R. Hager, R. Maingi, et al. Pressure balance in a lower collisionality, attached tokamak scrape-off layer. Nuclear Fusion 59, 096002 (2019)

  • R. Hager, J. Dominski, and C. S. Chang. Cross-verification of neoclassical transport solutions from XGCa against NEO. Physics of Plasmas 26, 104502 (2019)

  • R. Hager, C. S. Chang, N. Ferraro, and R. Nazikian. Gyrokinetic study of collisional resonant magnetic perturbation (RMP)-driven plasma density and heat transport in tokamak edge plasma using a magnetohydrodynamic screened RMP field. Nuclear Fusion 59, 126009 (2019)

2018

  • J.-M. Kwon, S. Ku, M. J. Choi, C. S. Chang, R. Hager, et al. Gyrokinetic simulation study of magnetic island effects on neoclassical physics and micro-instabilities in a realistic KSTAR plasma. Physics of Plasmas 25, 052506 (2018)

  • S. Ku, C. S. Chang, R. Hager, R. M. Churchill, G. R. Tynan, et al. A fast low-to-high confine- ment mode bifurcation dynamics in the boundary-plasma gyrokinetic code XGC1. Physics of Plasmas 25, 056107 (2018)

  • I. K. Charidakos, J. R. Myra, S. Parker, S. Ku, R. M. Churchill, et al. Analysis of equilibrium and turbulent fluxes across the separatrix in a gyrokinetic simulation. Physics of Plasmas 25, 072306 (2018)

2017

  • D. Stotler, D. Battaglia, R. Hager, K. Kim, T. Koskela, et al. Kinetic neoclassical calculations of impurity radiation profiles. Nuclear Materials and Energy 12, 1130 (2017)

  • X. Litaudon, S. Abduallev, M. Abhangi, P. Abreu, M. Afzal, et al. Overview of the JET results in support to ITER. Nuclear Fusion 57, 102001 (2017)

  • R. Churchill, J. Canik, C. Chang, R. Hager, A. Leonard, et al. Total fluid pressure imbalance in the scrape-off layer of tokamak plasmas. Nuclear Fusion 57, 046029 (2017)

  • R. Churchill, J. Canik, C. Chang, R. Hager, A. Leonard, et al. Kinetic simulations of scrape-off layer physics in the DIII-D tokamak. Nuclear Materials and Energy 12, 978 (2017)

  • C. Chang, S. Ku, G. Tynan, R. Hager, R. Churchill, et al. Fast Low-to-High Confinement Mode Bifurcation Dynamics in a Tokamak Edge Plasma Gyrokinetic Simulation. Physical Review Letters 118, 175001 (2017)

  • R. Hager, J. Lang, C. S. Chang, S. Ku, Y. Chen, et al. Verification of long wavelength electromagnetic modes with a gyrokinetic-fluid hybrid model in the XGC code. Physics of Plasmas 24, 054508 (2017)

  • C.S. Chang, S. Ku, A. Loarte, V. Parail, F. Köchl, M. Romanelli, R. Maingi, J.-W. Ahn, T. Gray, J. Hughes, B. LaBombard, T. Leonard, M. Makowski, J. Terry. Gyrokinetic projection of the divertor heat-flux width from present tokamaks to ITER. Nucl. Fusion 57, 116023 (2017)

  • Kyuho Kim, Jae-Min Kwon, C. S. Chang, Janghoon Seo, S. Ku, and W. Choe. Full-f XGC1 gyrokinetic study of improved ion energy confinement from impurity stabilization of ITG turbulence. Phys. Plasmas 24, 062302 (2017)

  • Jonathan Menard. Overview of NSTX Upgrade Initial Results and Modelling Highlights. Nuclear Fusion 57, 102006 (2017)

  • A.Y. Pankin, T. Rafiq , A. H. Kritz , G. Y. Park , P. B. Snyder , and C. S. Chang. Investigation of the plasma shaping effects on the H-mode pedestal structure using coupled kinetic neoclassical/MHD stability simulations. Phys. Plasmas 24, 062502 (2017)

  • D.P. Stotler, J. Lang, C.S. Chang, R.M. Churchill and S. Ku. Neutral recycling effects on ITG turbulence. Nuclear Fusion 57, 086028 (2017)

2016

  • R. Hager, E. Yoon, S. Ku, E. D’Azevedo, P. Worley, et al. A fully non-linear multi-species Fokker-Planck-Landau collision operator for simulation of fusion plasma. Journal of Computational Physics 315, 644 (2016)

  • R. Hager and C. S. Chang. Gyrokinetic neoclassical study of the bootstrap current in the tokamak edge pedestal with fully non-linear Coulomb collisions. Physics of Plasmas 23, 042503 (2016)

  • S. Ku, R. Hager, C. Chang, J. Kwon, and S. Parker. A new hybrid-Lagrangian numerical scheme for gyrokinetic simulation of tokamak edge plasma. Journal of Computational Physics 315, 467 (2016)

  • D. J. Battaglia, K. H. Burrell, C. S. Chang, J. S. deGrassie, B. A. Grierson, et al. Improved kinetic neoclassical transport calculation for a low-collisionality QH-mode pedestal. Plasma Physics and Controlled Fusion 58, 085009 (2016)

  • M. Romanus, S. Klasky, C.-S. Chang, I. Rodero, F. Zhang, et al. Persistent Data Staging Services for Data Intensive In-situ Scientific Workflows. In Proceedings of the ACM International Workshop on Data-Intensive Distributed Computing - DIDC ’16. ACM Press (2016)

  • Tyson Neuroth, Franz Sauer, Weixng Wang, Stephane Ethier, C.S. Chang, Kwan-Liu Ma. Scalable Visualization of Time-varying Multi-parameter Distributions Using Spatially Organized Histograms. IEEE Transactions on Visualization and Computer Graphics, p. 1, (2016)

  • S. A. Klasky, Hasan Abbasi, M. Ainsworth, Jong Youl Choi, Matthew Curry, T. Kurc, Q. Liu, Jay Lofstead, Carlos Maltzahn, Manish Parashar, Norbert Podhorszki, Eric Suchyta, F. Wang, M. Wolf, C.S. Chang, R. Churchill, Stephane Ethier. Exascale Storage Systems the SIRIUS Way. Journal of Physics, Conference Series, 759, 012095 (2016)

  • Lingfei Wu, Kesheng Wu, Alex Sim, Michael Churchill, Jong Y. Choi, Andreas Stathopoulos, CS Chang, and Scott Klasky. Towards Real-Time Detection and Tracking of Blob-Filaments in Fusion Plasma Big Data. IEEE Transactions on Big Data, volume 2, p. 262 (2016)

  • Michael Sprague, Stanislav Boldyrev, C.S. Chang, Paul F. Fischer, Ray Grout, Willian I. Gustafson, Jeffrey Hittinger, Elia Merzari, Robert Moser. Outcomes from the DOE Workshop on Turbulent Flow Simulation at the Exascale (2016)

  • Kyuho Kim, C. S. Chang, Janghoon Seo, S. Ku, and W. Choe. What happens to full-f gyrokinetic transport and turbulence in a toroidal wedge simulation? Phys. Plasmas 24, 012306 (2017)

2015

  • R. M. Churchill, C. Theiler, B. Lipschultz, I. H. Hutchinson, M. L. Reinke, et al. Poloidal asymmetries in edge transport barriers. Physics of Plasmas 22, 056104 (2015)

  • F. Zhang, R. Hager, S.-H. Ku, C.-S. Chang, S. C. Jardin, et al. Mesh generation for confined fusion plasma simulation. Engineering with Computers 32, 285 (2015)

  • T. Jin, F. Zhang, Q. Sun, H. Bui, M. Romanus, et al. Exploring Data Staging Across Deep Memory Hierarchies for Coupled Data Intensive Simulation Workflows. In 2015 IEEE Interna- tional Parallel and Distributed Processing Symposium. IEEE (2015)

  • A. Pankin, T. Rafiq, A.H. Kritz, G.Y. Park, S. Ku, C.S. Chang, D. Brunner, J.W. Hughes, B. LaBombard, J.L. Terry, and R.J. Groebner. Kinetic Modeling of Divertor Heat Load Fluxes in the Alcator C-Mod and DIII-D Tokamaks. Phys. Plasmas 22, 092511 (2015)

  • Stephane Ethier, Choong-Seock Chang et al. NERSC's Impact on Advances of Global Gyrokinetic PIC Codes for Fusion Energy Research. Computing in Science & Engineering 17, 10 (2015)

2014

  • Janghoon Seo, C.S. Chang, S. Ku, J.M. Kwon, W. Choe. Intrinsic momentum generation by a combined neoclassical and turbulence mechanism in diverted DIII-D plasma edge. Physics of Plasmas 21, 092501 (2014)

  • D.J. Battaglia, K.H. Burrell, C.S. Chang, S. Ku, J.S. deGrassie, and B.A. Grierson. Kinetic Neoclassical Transport in the H-mode Pedestal. Phys. Plasmas 21, 072508 (2014)

  • E.S. Yoon and C.S. Chang. A Fokker-Planck-Landau collision equation solver on two-dimensional velocity grid and its application to particle-in-cell simulation. Phys. Plasmas 21, 032503 (2014)

2013

  • D. P. Stotler, C. S. Chang, S. H. Ku, J. Lang and G. Park Energy conservation tests of a coupled kinetic plasma-kinetic neutral transport code. Comput. Sci. Disc. 6, 015006 (2013)

  • D. P. Stotler, C. S. Chang, S. H. Ku, J. Lang and G. Y. Park Pedestal fueling simulations with a coupled kinetic plasma-kinetic neutral transport code. J. Nucl. Mater. 438, S1275 (2013)

  • D. J. Battaglia, C.S. Chang, S.M. Kaye, K. Kim, S. Ku, R. Maingi, R.E. Bell, A. Diallo, S. Gerhardt, B.P. LeBlanc, J. Menard, M. Podesta, and the NSTX Team. Dependence of the L-H Transition on X-point Geometry and DivertorRecycling on NSTX. Nucl. Fusion 53, 113032 (2013)

2012

  • S. Ku, J. Abiteboul, P.H. Diamond, G. Dif-Pradalier, J.M. Kwon, Y. Sarazin, T.S. Hahm, X. Garbet, C.S. Chang, G. Latu, E.S. Yoon, Ph. Ghendrih, S. Yi, A. Strugarek, W. Solomon and V. Grandgirard. Physics of intrinsic rotation in flux-driven ITG turbulence. Nucl. Fusion 52, 063013 (2012)

  • S. Koh , C. S. Chang , S. Ku , J. E. Menard , H. Weitzner, W. Choe. Phys. Plasmas 19, 072505 (2012)

  • W. Wan, S. E. Parker, Y. Chen et al. Global Gyrokinetic Simulation of Tokamak Edge Pedestal Instabilities. Phys. Rev. Lett. 109, 185004 (2012)

2011

  • S. M. Kaye, R. Maingi, D. Battaglia, R.E. Bell, C.S. Chang, J. Hosea, H. Kugel, B.P. LeBlanc, H. Meyer, G.Y. Park, and J.R. Wilson. L-H threshold studies in NSTX. Nucl. Fusion 51, 113109 (2011)

  • G. Dif-Pradalier, J. Gunn, G. Ciraolo, C.S. Chang, G. Chiavassa, P. Diamond, N. Fedorczak, Ph. Ghendrih, L. Isoardi, M. Kocan, S. Kud, E. Serre, P. Tamain , Tore Supra Team. The Mistral base case to validate kinetic and fluid turbulence transport codes of the edge and SOL plasmas. Journal of Nuclear Materials 415, S597–S600 (2011)

  • Sriram Lakshminarasimhan, John Jenkins, Isha Arkatkar, Zhenhuan Gong, Hemanth Kolla, Seung-Hoe Ku, Stephane Ethier, Jackie Chen, C.S. Chang, Scott Klasky, Robert Latham, Robert Ross, and Nagiza F. Samatova,. ISABELA-QA: Query-driven Analytics with ISABELA-compressed Extreme-Scale Scientific Data. Super Computing 2011

  • Ye Jin, Sriram Lakshminarasimhan, Neil Shah, Zhenhuan Gong, C.S. Chang, Jackie Chen, Stephane Ethier, Hemanth Kolla, Seung-Hoe Ku, Scott Klasky, Robert Latham, Robert Ross, Karen Schuchardt, Nagiza F. Samatova. S-preconditioner for Multi-fold Data Reduction with Guaranteed User-controlled Accuracy. ICDM 2011

  • Y. Sarazin, V. Grandgirard, J. Abiteboul, S. Allfrey, X. Garbet, Ph. Ghendrih, G. Latu, A. Strugarek, G. Dif-Pradalier, P.H. Diamond, S. Ku, C.S. Chang, B F McMillan, T M Tran, L Villard, S Jolliet, A Bottino, P Angelino, Predictions on heat transport and plasma rotation from global gyrokinetic simulations. Nuclear Fusion 51, 103023 (2011)

  • Weigang Wan, Scott E. Parker, Y. Chen, G.Y. Park, C.S. Chang, D. Stotler. The pinch of cold ions from recycling in the tokamak edge pedestal. Phys. Plasmas 18, 056116 (2011)

  • G. Dif-Pradalier, P. H. Diamond,b) V. Grandgirard, Y. Sarazin, J. Abiteboul, X. Garbet, Ph. Ghendrih, G. Latu, A. Strugarek, S. Ku, and C. S. Chang. Neoclassical physics in full distribution function gyrokinetics. Physics of Plasmas 18, 062309 (2011)

  • R. F. Schmitt, L. Guazzotto, H. Strauss, G. Y. Park, and C.-S. Chang. Free-boundary magnetohydrodynamic equilibria with flow. Phys. Plasmas 18, 022502 (2011)

2010

  • G. Dif-Pradalier, P. H. Diamond, V. Grandgirard, Y. Sarazin, J. Abiteboul, X. Garbet, Ph. Ghendrih, and A. Strugarek, S. Ku and C. S. Chang. On the validity of the local diffusive paradigm in turbulent plasma transport. Phys. Rev. E 82, 025401(R) (2010)

  • G.Y. Park, C.S. Chang, I. Joseph, and R. Moyer. Plasma transport in stochastic magnetic field caused by vacuum resonant magnetic perturbations at diverted tokamak edge. Physics of Plasmas 17, 102503 (2010)

  • R. Maingi, S.M. Kaye, R.E. Bell, T.M. Biewer, C.S. Chang, D.A. et al, Overview of L–H power threshold studies in NSTX. Nucl. Fusion 50, 064010 (2010)

2009

  • D.A. Gates, et al, C. Chang among many authors. Overview of results from the National Spherical Torus Experiment (NSTX). Nucl. Fusion 49, 104016 (2009)

  • X. Q. Xu, E. Belli, K. Bodi, J. Candy, C. S. Chang, B. I. Cohen, R. H. Cohen, P. Colella, A. M. Dimits, M. R. Dorr, Z. Gao, J. A. Hittinger, S. Ko, S. Krasheninnikov, G. R. McKee, W. M. Nevins, T. D. Rognlien, P. B. Snyder, J. Suh, M. V. Umansky. Dynamics of kinetic Geodesic-Acoustic modes and the radial electric field in tokamak neoclassical plasmas. Nuclear Fusion 49, 065023 (2009)

  • S. Ku, C.S. Chang, and P.H. Diamond. Full-f gyrokinetic particle simulation of centrally heated global ITG turbulence from magnetic axis to edge pedestal top in a realistic tokamak geometry. Nuclear Fusion 49, 115021 (2009)

  • H.R. Strauss, L. Sugiyama, G.Y. Park, C.S.Chang, S. Ku, and I. Joseph, Extended MHD simulation or resonant magnetic perturbations. Nuclear Fusion 49, 055025 (2009)

  • C. S. Chang,, S. Ku, P. H. Diamond, Z. Lin, S. Parker, T. S. Hahm and N. Samatova. Compressed ion temperature gradient turbulence in diverted tokamak edge. Phys. Plasmas 16, 056108 (2009)

  • M. Adams, S. Ku, P. Worley, D'Azevedo, J. Cummings, C.S. Chang. Scaling to 150K cores: recent algorithm and performance engineering developments enabling XGC1 to run at scale. Journal of Physics: Conference Series 180, 012036 (2009)

  • C.S. Chang, S. Ku, et al, P. Diamond, M. Adams, R. Barreto, Y. Chen, J. Cummings, E. D'Azevedo, G. Dif-Pradalier, S. Ethier, L. Greengard, T. S. Hahm, F. Hinton, D. Keyes, S. Klasky, Z. Lin, J. Lofstead, G. Park, S. Parker, N. Podhorszki, K. Schwan, A. Shoshani, D. Silver, M. Wolf, P. Worley, H. Weitzner, E. Yoon and D. Zorin. Whole Volume Integrated Simulation of Plasma Turbulence in Realistic Diverted-Tokamak Geometry. Journal of Physics: Conference Series 180, 012057 (2009)

2008

  • C S Chang, S Klasky, J Cummings, et al. Toward a first-principles integrated simulation of tokamak edge Plasmas. J. Phys: Conf. Series 125, 012042 (2008)

  • J. Cummings, A. Pankin, N. Podhorszki, G. Park, S. Ku, R. Barreto, S. Klasky, C. S. Chang, H. Strauss, L. Sugiyama, P. Snyder, D. Pearlstein, B. Ludascher, G. Bateman, A. Kritz and the CPES Team. Plasma Edge Kinetic-MHD Modeling in Tokamaks Using Kepler Workflow for Code Coupling, Data Management and Visualization. Commun. Comput. Phys. 4, 675 (2008)

  • C.S. Chang, S. Ku. Spontaneous rotation sources in a quiescent tokamak edge plasma. Phys. Plasmas 15, 062510 (2008)

  • Y. Chen, S. E. Parker, G. Rewoldt, S. Ku, G. Y. Park, C-S Chang. Coarse-graining the electron distribution in gyrokinetic simulations. Phys. Plasmas 15, 055905 (2008)

2007

  • J. E. Menard, M.G. Bell, R.E. Bell, …, C.S. Chang, et al. Overview of recent physics results from the National Spherical Torus Experiment (NSTX). Nuclear Fusion 47, S645 (2007)

  • G. Park, J. Cummings, C.S. Chang, Podhorszki, S. Klasky, etc. Coupled simulation of kinetic pedestal growth and MHD ELM crash. Journal of Physics: Conference Series 78, 012087 (2007)

  • D.A. Batchelor, M. Beck, A. Becoulet, R.V. Budny, C.S. Chang, et al. Simulation of Fusion Plasmas: Current Status and Future Direction. Plasma Science and Technology 9, 312 (2007)

  • Gunyoung Park and C.S. Chang. A 5-1/2-dimensional theory for fast and accurate evaluation of the cyclotron resonance heating using real-space wave representation. Phys. Plasmas 14, 052503 (2007)

2006

  • S. Ku, C.S. Chang, M. Adams, et al. Gyrokinetic particle simulation of neoclassical transport in the pedestal/scrape-off region of a tokamak plasma. Journal of Physics: Conference Series 46 (2006) 87

  • C. S. Chang and S. Ku. Particle simulation of neoclassical transport in the plasma edge. Contrib. Plasma Phys. 46, 496–503 (2006)

  • Hoyul Baek, Seunghoe Ku and C.S. Chang. Neoclassical polarization drift of collisionless single ions in a sheared radial electric field in a tokamak magnetic geometry. Phys. Plasmas 13, 012503 (2006)

2005

  • S.H. Hahn, Seunghoe Ku and C.S. Chang. Wall intersection of ion orbits induced by fast transport of pedestal plasma over an electrostatic potential hill in a tokamak plasma edge. Physics of Plasmas 12, 102501 (2005)

  • Harold Weitzner and C.S. Chang. Extension of adiabatic invariant theory for a charged particle. Phys. Plasmas 12, 012106 (2005)

2004

  • S.H. Ku and C. S. Chang. Property of an X-point generated velocity space hole in a diverted tokamak plasma edge. Phys. Plasmas 11, 5626 (2004)

  • C. S. Chang, Seunghoe Ku, and H. Weitzner. Numerical study of neoclassical plasma pedestal in a tokamak geometry. Phys. Plasmas APS Invited Issue 11, 2649 (2004)

  • H. Weitzner and C. S. Chang. Single particle motion near separatrix and X-point. Phys. Plasmas 11, 3060 (2004)

  • R. Maingi, C. S. Chang, Seunghoe Ku, et al. Effect of gas fueling location on H-mode Access in NSTX. Plasma Phys. Cont. Fusion 46, A305-A313 (2004)

  • S. Hahn, G. Park, C. S. Chang, C. K. Choi. Diffusion in a two-dimensional anisotropic web map by extrinsic noise applied to the intrinsically perturbed quantity. Phys. Rev. E 69, 017202 (2004)

2003

  • Gunyoung Park and C. S. Chang. Numerical study of collisional ripple diffusion in a tokamak plasma. Phys. Plasmas 10, 4004 (2003)

2002

  • C.S. Chang, Seunghoe Kue, and H. Weitzner. X-Transport: A baseline transport in a diverted tokamak plasma edge. Phys. Plasmas 9, 3884 (2002)