Self-consistent edge-wall simulations with WALLPSI in FACETS (original) (raw)
Coupled whole device simulations of plasma transport in tokamaks with the FACETS code
Proceedings of SciDAC …, 2010
The FACETS project aims to provide computational tools for whole device simulation of tokamak transport for use in fusion applications. The framework provides flexibility by allowing users to choose the best model for a given physics target. Our goals are to develop accurate transport solvers using neoclassical and turbulent fluxes with varying degree of fidelity and computational complexity, including embedded gyrokinetic models. Accurate sources using both ICRH wave absorption and neutral beam injection, using parallel source components, are included. Modeling of the plasma edge using a fluid based component, UEDGE, is performed and coupled to the core solver. The core region is simulated using a newly developed parallel, nested iteration based nonlinear solver while the UEDGE uses nonlinear solves from the PETSc/SNES solver package. As a first application we present coupled core-edge simulations of pedestal buildup in the DIIID tokamak.
Introducing FACETS, the Framework Application for Core-Edge Transport Simulations
Journal of Physics: Conference Series, 2007
The FACETS (Framework Application for Core-Edge Transport Simulations) project began in January 2007 with the goal of providing core to wall transport modeling of a tokamak fusion reactor. This involves coupling previously separate computations for the core, edge, and wall regions. Such a coupling is primarily through connection regions of lower dimensionality. The project has started developing a component-based coupling framework to bring together models for each of these regions. In the first year, the core model will be a 1 ½ dimensional model (1D transport across flux surfaces coupled to a 2D equilibrium) with fixed equilibrium. The initial edge model will be the fluid model, UEDGE, but inclusion of kinetic models is planned for the out years. The project also has an embedded Scientific Application Partnership that is examining embedding a full-scale turbulence model for obtaining the crosssurface fluxes into a core transport code.
The European transport solver: an integrated approach for transport simulations in the plasma core
The "European Transport Solver" (ETS) [1,2] is the new modular simulator developed within the EFDA Integrated Tokamak Modelling (ITM) Task Force*. Ultimately, it will allow for the entire discharge simulation from the start up until the current termination phase, including controllers and subsystems. The paper presents the current status of the project towards this ultimate goal. It discusses the design of the workflow, verification and validation of integrated modules. It presents the first results obtained on impurity simulations and on neoclassical tearing modes, as well as the "proof of principle" tests performed on transport-free boundary equilibrium coupling and on transport-turbulence coupled simulations.
A second generation code for modeling tokamak edge plasmas
Journal of Nuclear Materials, 1992
We describe the development and status of our "second generation" tokamak plasma edge modeling code, UCLA-EMS. The design goals are flexible geometric modeling, robust and efficient numerics, easy alteration of modeling equations, and ease of use, via a graphical user interface. Fluid equations are discretized using a finite element-control volume hybrid method on a general quadrilateral mesh, not necessarily aligned with flux surfaces. The resulting nonlinear equations are solved using a Newton's method, and the linearized system resulting at each Newton iteration is solved by a preconditioned conjugate gradient method.
Framework Application for Core Edge Transport Simulation (FACETS)
2012
The goal of the FACETS project (Framework Application for Core-Edge Transport Simulations) was to provide a multiphysics, parallel framework application (FACETS) that will enable whole-device modeling for the U.S. fusion program, to provide the modeling infrastructure needed for ITER, the next step fusion confinement device. Through use of modern computational methods, including component technology and object oriented design, FACETS is able to switch from one model to another for a given aspect of the physics in a flexible manner. This enables use of simplified models for rapid turnaround or high-fidelity models that can take advantage of the largest supercomputer hardware. FACETS does so in a heterogeneous parallel context, where different parts of the application execute in parallel by utilizing task farming, domain decomposition, and/or pipelining as needed and applicable. ParaTools, Inc. was tasked with supporting the performance analysis and tuning of the FACETS components and framework in order to achieve the parallel scaling goals of the project. The TAU Performance System ® was used for instrumentation, measurement, archiving, and profile / tracing analysis. ParaTools, Inc. also assisted in FACETS performance engineering efforts. Through the use of the TAU Performance System, ParaTools provided instrumentation, measurement, analysis and archival support for the FACETS project. Performance optimization of key components has yielded significant performance speedups. TAU was integrated into the FACETS build for both the full coupled application and the UEDGE component. The performance database provided archival storage of the performance regression testing data generated by the project, and helped to track improvements in the software development.
The goal of the Integrated Tokamak Modelling (ITM) Task Force [1] is to provide the European fusion community with a suite of validated codes for the support of the European fusion program, ultimately, to enable the complete simulation of the discharge in a tokamak like ITER including the core, the edge and the scrape-off layer (tokamak simulator). Such a simulator should adopt a modular approach, when stand alone physics and numeric modules are communicating to each other via standardized interfaces linked with the ITM agreed data structure. These principles are used in the construction of the new European Transport Solver (ETS), prepared to solve 1-D transport equations for the core plasma. Besides of high degree of modularity, the ETS should meet other requirements: ability to treat several ion components, ultimately including all impurity species; ability to
A 3D finite volume scheme for the simulation of edge plasma in Tokamaks
ESAIM: Proceedings, 2013
Une méthode de volumes finis en coordonnées cylindriques pour la simulation de la région du bord dans les tokamaks est proposé. Contrairement aux méthodes classiques, qui sont basés sur la projection deséquations en coordonnées curvilignes, une nouvelle méthode est proposée ici. Cette technique est basée sur la discrétisation de la forme vectorielle deséquations et ensuite sur la projection sur les vecteurs de base du systéme curviligne associéà chaque volume de contrôle. La Méthodologie proposée aété validée sur plusieurs cas-tests simples et appliqué sur une simulation 3D d'un modèle MHD réduit.
In this paper we present the main issues concerning our research activity on tokamak plasmas and numerical simulation. The long term scope of our effort is to develop a 3D simulation code of the edge plasma-wall interaction including turbulent transport. This versatile numerical tool will address the physics in a simplified cylindrical geometry (limiter geometry). This code is also used as a test bed to implement novel numerical schemes that will be successively taken into account by the future (ITER horizon) ESPOIR code for full ITER geometry developed in the framework of the ANR project ESPOIR (ANR-09-BLAN-0035-01, 2009-2013).
Challenges in plasma edge fluid modelling
Plasma Physics and Controlled Fusion, 2007
Plasma fluid models like B2, UEDGE or EDGE2D are the standard tools for simulation of scrape-off layer physics, both for design and experimental support. The concept of a numerical tokamak, aiming at a predictive code for ITER, triggers the need to re-assess the available tools and their necessary extensions. These additional physics issues will be summarized. The experience existing in other scientific fields with multi-scale problems and modelling should be used as a guide. Here, the coupling strategies are in particular of interest for fusion problems. As a consequence, a certain construction of integrated modelling codes is needed: depending on the specific problem, models allowing different levels of complexity will be needed. Therefore, a hierarchy of tools is necessary, which will be discussed.
Advanced Methods for the Evaluation of the Heat Flux Distribution onto the First Wall of a Tokamak
Proc. of XXIV Congresso Nazionale UIT sulla …, 2006
We present a new computational code for the evaluation of heat fluxes on the first wall of a tokamak reactor. The method applies the Control-Volumes Finite-Element (CVFE) approach to the solution of the plasma fluid equations on the tokamak edge. The CVFE approach is particularly suited for application to triangular meshes, and allows extending the computational grid up to the physical wall of the reactor. As a consequence, it enables studying the Plasma-Wall Interactions (PWI) in full geometrical detail, as opposed to the presently most popular codes, which oversimplify the external wall shape on most of its extension. The new code was developed to study the heat flux deposition onto the IGNITOR First-Wall/Limiter, but has a number of other potential applications, including the limiter start-up phase of the International Thermonuclear Experimental Reactor (ITER), the power deposition onto the external wall driven by Edge Localized Modes (ELMs). Here we discuss the method, illustrate its geometrical potentialities on a simple test case, and present the first application to the analysis of the IGNITOR tokamak first-wall/limiter.