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Title: Final report on work for Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas — Tools for Improved Data Logistics

Abstract

This project focused on the use of Logistical Networking technology to address the challenges involved in rapid sharing of data from the the Center's gyrokinetic particle simulations, which can be on the order of terabytes per time step, among researchers at a number of geographically distributed locations. There is a great need to manage data on this scale in a flexible manner, with simulation code, file system, database and visualization functions requiring access. The project used distributed data management infrastructure based on Logistical Networking technology to address these issues in a way that maximized interoperability and achieved the levels of performance the required by the Center's application community. The work focused on the development and deployment of software tools and infrastructure for the storage and distribution of terascale datasets generated by simulations running at the National Center for Computational Science at Oak Ridge National Laboratory.

Authors:
Publication Date:
Research Org.:
Univ. of Tennessee, Knoxville, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
947004
Report Number(s):
DOE/ER/25651-1 Final Report
TRN: US201012%%1149
DOE Contract Number:
FG02-04ER25651
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DATA; DISTRIBUTION; FUNCTIONS; LEVELS; MANAGEMENT; ORDERS; ORNL; PARTICLES; PERFORMANCE; SIMULATION; STORAGE; TOOLS; TRANSPORT; USES; WORK

Citation Formats

Micah Beck. Final report on work for Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas — Tools for Improved Data Logistics. United States: N. p., 2008. Web. doi:10.2172/947004.
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Micah Beck. Final report on work for Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas — Tools for Improved Data Logistics. United States. doi:10.2172/947004.
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Micah Beck. Sun . "Final report on work for Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas — Tools for Improved Data Logistics". United States. doi:10.2172/947004. https://www.osti.gov/servlets/purl/947004.
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@article{osti_947004,
title = {Final report on work for Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas — Tools for Improved Data Logistics},
author = {Micah Beck},
abstractNote = {This project focused on the use of Logistical Networking technology to address the challenges involved in rapid sharing of data from the the Center's gyrokinetic particle simulations, which can be on the order of terabytes per time step, among researchers at a number of geographically distributed locations. There is a great need to manage data on this scale in a flexible manner, with simulation code, file system, database and visualization functions requiring access. The project used distributed data management infrastructure based on Logistical Networking technology to address these issues in a way that maximized interoperability and achieved the levels of performance the required by the Center's application community. The work focused on the development and deployment of software tools and infrastructure for the storage and distribution of terascale datasets generated by simulations running at the National Center for Computational Science at Oak Ridge National Laboratory.},
doi = {10.2172/947004},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Sep 14 00:00:00 EDT 2008},
month = {Sun Sep 14 00:00:00 EDT 2008}
}
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Technical Report:
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DOI:  10.2172/947004
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  • During the first year of the SciDAC gyrokinetic particle simulation (GPS) project, the GPS team (Zhihong Lin, Liu Chen, Yasutaro Nishimura, and Igor Holod) at the University of California, Irvine (UCI) studied the tokamak electron transport driven by electron temperature gradient (ETG) turbulence, and by trapped electron mode (TEM) turbulence and ion temperature gradient (ITG) turbulence with kinetic electron effects, extended our studies of ITG turbulence spreading to core-edge coupling. We have developed and optimized an elliptic solver using finite element method (FEM), which enables the implementation of advanced kinetic electron models (split-weight scheme and hybrid model) in the SciDACmore » GPS production code GTC. The GTC code has been ported and optimized on both scalar and vector parallel computer architectures, and is being transformed into objected-oriented style to facilitate collaborative code development. During this period, the UCI team members presented 11 invited talks at major national and international conferences, published 22 papers in peer-reviewed journals and 10 papers in conference proceedings. The UCI hosted the annual SciDAC Workshop on Plasma Turbulence sponsored by the GPS Center, 2005-2007. The workshop was attended by about fifties US and foreign researchers and financially sponsored several gradual students from MIT, Princeton University, Germany, Switzerland, and Finland. A new SciDAC postdoc, Igor Holod, has arrived at UCI to initiate global particle simulation of magnetohydrodynamics turbulence driven by energetic particle modes. The PI, Z. Lin, has been promoted to the Associate Professor with tenure at UCI.« less

  • ; ; ; ...
    “We propose to further develop the global, particle-in-cell, gyrokinetic toroidal code (GTC) for simulations of plasma turbulence and transport, and to advance understanding and our ability to control radial transport of heat, momentum, and particles in magnetically confined plasmas with temperatures up to those required for nuclear fusion power production regimes called burning plasmas. Building on the excellent physics capabilities and high performance computing, GTC will be extensively applied to simulate experimentally relevant parameter regimes including electromagnetic fluctuations, kinetic electrons, multiple ion species, realistic collision operators, and shaped plasmas. Collaborative code development will be pursued to accelerate implementations of newmore » physics capabilities including long time steady state simulation with profile evolution, and core-edge coupling. The new simulation capabilities and access to tera- and petascale computers will allow us to address new physics and parameter regimes important for burning plasma experiments such as International Thermonuclear Experimental Reactor (ITER).” Among the three key goals and objectives (code development, comprehensive physics simulation, and core-edge coupling), we have achieved fully the first two goals, namely, 1. “to further develop the global, particle-in-cell, gyrokinetic toroidal code (GTC) for simulations of plasma turbulence and transport, and to advance understanding and our ability to control radial transport of heat, momentum, and particles in magnetically confined plasmas with temperatures up to those required for nuclear fusion power production regimes called burning plasmas.” 2. “GTC will be extensively applied to simulate experimentally relevant parameter regimes including electromagnetic fluctuations, kinetic electrons, multiple ion species, realistic collision operators, and shaped plasmas.” Regarding the third objective, 3. “Collaborative code development will be pursued to accelerate implementations of new physics capabilities including long time steady state simulation with profile evolution, and core-edge coupling.” While we have productively engaged in collaborative code development and made satisfactory progress on implementing new physics including long time steady state simulation with profile evolution, we have not achieved the goal of core-edge coupling.« less

  • The goal of this project is the development of the Gyrokinetic Toroidal Code (GTC) Framework and its applications to problems related to the physics of turbulence and turbulent transport in tokamaks,. The project involves physics studies, code development, noise effect mitigation, supporting computer science efforts, diagnostics and advanced visualizations, verification and validation. Its main scientific themes are mesoscale dynamics and non-locality effects on transport, the physics of secondary structures such as zonal flows, and strongly coherent wave-particle interaction phenomena at magnetic precession resonances. Special emphasis is placed on the implications of these themes for rho-star and current scalings and formore » the turbulent transport of momentum. GTC-TTBP also explores applications to electron thermal transport, particle transport; ITB formation and cross-cuts such as edge-core coupling, interaction of energetic particles with turbulence and neoclassical tearing mode trigger dynamics. Code development focuses on major initiatives in the development of full-f formulations and the capacity to simulate flux-driven transport. In addition to the full-f -formulation, the project includes the development of numerical collision models and methods for coarse graining in phase space. Verification is pursued by linear stability study comparisons with the FULL and HD7 codes and by benchmarking with the GKV, GYSELA and other gyrokinetic simulation codes. Validation of gyrokinetic models of ion and electron thermal transport is pursed by systematic stressing comparisons with fluctuation and transport data from the DIII-D and NSTX tokamaks. The physics and code development research programs are supported by complementary efforts in computer sciences, high performance computing, and data management.« less

  • The UCLA work on this grant was to design and help implement an object-oriented version of the GTC code, which is written in Fortran90. The GTC code is the main global gyrokinetic code used in this project, and over the years multiple, incompatible versions have evolved. The reason for this effort is to allow multiple authors to work together on GTC and to simplify future enhancements to GTC. The effort was designed to proceed incrementally. Initially, an upper layer of classes (derived types and methods) was implemented which called the original GTC code 'under the hood.' The derived types pointedmore » to data in the original GTC code, and the methods called the original GTC subroutines. The original GTC code was modified only very slightly. This allowed one to define (and refine) a set of classes which described the important features of the GTC code in a new, more abstract way, with a minimum of implementation. Furthermore, classes could be added one at a time, and at the end of the each day, the code continued to work correctly. This work was done in close collaboration with Y. Nishimura from UC Irvine and Stefan Ethier from PPPL. Ten classes were ultimately defined and implemented: gyrokinetic and drift kinetic particles, scalar and vector fields, a mesh, jacobian, FLR, equilibrium, interpolation, and particles species descriptors. In the second state of this development, some of the scaffolding was removed. The constructors in the class objects now allocated the data and the array data in the original GTC code was removed. This isolated the components and now allowed multiple instantiations of the objects to be created, in particular, multiple ion species. Again, the work was done incrementally, one class at a time, so that the code was always working properly. This work was done in close collaboration with Y. Nishimura and W. Zhang from UC Irvine and Stefan Ethier from PPPL. The third stage of this work was to integrate the capabilities of the various versions of the GTC code into one flexible and extensible version. To do this, we developed a methodology to implement Design Patterns in Fortran90. Design Patterns are abstract solutions to generic programming problems, which allow one to handle increased complexity. This work was done in collaboration with Henry Gardner, a computer scientist (and former plasma physicist) from the Australian National University. As an example, the Strategy Pattern is being used in GTC to support multiple solvers. This new code is currently being used in the study of energetic particles. A document describing the evolution of the GTC code to this new object-oriented version is available to users of GTC.« less

  • ; ; ; ...
    The three-year project GPS-TTBP resulted in over 152 publications and 135 presentations. This summary focuses on the scientific progress made by the project team. A major focus of the project was on the physics intrinsic rotation in tokamaks. Progress included the first ever flux driven study of net intrinsic spin-up, mediated by boundary effects (in collaboration with CPES), detailed studies of the microphysics origins of the Rice scaling, comparative studies of symmetry breaking mechanisms, a pioneering study of intrinsic torque driven by trapped electron modes, and studies of intrinsic rotation generation as a thermodynamic engine. Validation studies were performed withmore » C-Mod, DIII-D and CSDX. This work resulted in very successful completion of the FY2010 Theory Milestone Activity for OFES, and several prominent papers of the 2008 and 2010 IAEA Conferences. A second major focus was on the relation between zonal flow formation and transport non-locality. This culminated in the discovery of the ExB staircase - a conceptually new phenomenon. This also makes useful interdisciplinary contact with the physics of the PV staircase, well-known in oceans and atmospheres. A third topic where progress was made was in the simulation and theory of turbulence spreading. This work, now well cited, is important for understanding the dynamics of non-locality in turbulent transport. Progress was made in studies of conjectured non-diffusive transport in trapped electron turbulence. Pioneering studies of ITB formation, coupling to intrinsic rotation and hysteresis were completed. These results may be especially significant for future ITER operation. All told, the physics per dollar performance of this project was quite good. The intense focus was beneficial and SciDAC resources were essential to its success.« less