A fully nonlinear multispecies Fokker–Planck–Landau collision operator for simulation of fusion plasma
Fusion edge plasmas can be far from thermal equilibrium and require the use of a nonlinear collision operator for accurate numerical simulations. The nonlinear singlespecies Fokker–Planck–Landau collision operator developed by Yoon and Chang (2014) [9] is generalized to include multiple particle species. Moreover, the finite volume discretization used in this work naturally yields exact conservation of mass, momentum, and energy. The implementation of this new nonlinear Fokker–Planck–Landau operator in the gyrokinetic particleincell codes XGC1 and XGCa is described and results of a verification study are discussed. Finally, the numerical techniques that make our nonlinear collision operator viable on highperformance computing systems are described, including specialized load balancing algorithms and nested OpenMP parallelization. As a result, the collision operator's good weak and strong scaling behavior are shown.
 Authors:

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 Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
 Rensselaer Polytechnic Inst., Troy, NY (United States)
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Publication Date:
 Report Number(s):
 PPPL5253
Journal ID: ISSN 00219991; PII: S0021999116300298
 Grant/Contract Number:
 AC0209CH11466; AC0500OR22725; SC0008449; AC0206CH11357; AC0205CH11231
 Type:
 Accepted Manuscript
 Journal Name:
 Journal of Computational Physics
 Additional Journal Information:
 Journal Volume: 315; Journal Issue: C; Journal ID: ISSN 00219991
 Publisher:
 Elsevier
 Research Org:
 Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
 Sponsoring Org:
 USDOE Office of Science (SC)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma; fusion; collision operator; XGC; particleincell; 97 MATHEMATICS AND COMPUTING
 OSTI Identifier:
 1254653
 Alternate Identifier(s):
 OSTI ID: 1295136; OSTI ID: 1325292
Hager, Robert, Yoon, E. S., Ku, S., D'Azevedo, E. F., Worley, P. H., and Chang, C. S.. A fully nonlinear multispecies Fokker–Planck–Landau collision operator for simulation of fusion plasma. United States: N. p.,
Web. doi:10.1016/j.jcp.2016.03.064.
Hager, Robert, Yoon, E. S., Ku, S., D'Azevedo, E. F., Worley, P. H., & Chang, C. S.. A fully nonlinear multispecies Fokker–Planck–Landau collision operator for simulation of fusion plasma. United States. doi:10.1016/j.jcp.2016.03.064.
Hager, Robert, Yoon, E. S., Ku, S., D'Azevedo, E. F., Worley, P. H., and Chang, C. S.. 2016.
"A fully nonlinear multispecies Fokker–Planck–Landau collision operator for simulation of fusion plasma". United States.
doi:10.1016/j.jcp.2016.03.064. https://www.osti.gov/servlets/purl/1254653.
@article{osti_1254653,
title = {A fully nonlinear multispecies Fokker–Planck–Landau collision operator for simulation of fusion plasma},
author = {Hager, Robert and Yoon, E. S. and Ku, S. and D'Azevedo, E. F. and Worley, P. H. and Chang, C. S.},
abstractNote = {Fusion edge plasmas can be far from thermal equilibrium and require the use of a nonlinear collision operator for accurate numerical simulations. The nonlinear singlespecies Fokker–Planck–Landau collision operator developed by Yoon and Chang (2014) [9] is generalized to include multiple particle species. Moreover, the finite volume discretization used in this work naturally yields exact conservation of mass, momentum, and energy. The implementation of this new nonlinear Fokker–Planck–Landau operator in the gyrokinetic particleincell codes XGC1 and XGCa is described and results of a verification study are discussed. Finally, the numerical techniques that make our nonlinear collision operator viable on highperformance computing systems are described, including specialized load balancing algorithms and nested OpenMP parallelization. As a result, the collision operator's good weak and strong scaling behavior are shown.},
doi = {10.1016/j.jcp.2016.03.064},
journal = {Journal of Computational Physics},
number = C,
volume = 315,
place = {United States},
year = {2016},
month = {4}
}