Self-consistent edge-wall simulations with WALLPSI in FACETS (original) (raw)
Related papers
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.
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.
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.
Physics of Plasmas, 2012
Coupled simulations of core and edge transport in the DIII-D shot number 118897, after the L-H transition but before the first edge localized mode (ELM), are presented. For the plasma core transport, a set of one dimensional transport equations are solved using the FACETS:Core solver. The fluxes in this region are calculated using the GLF23 anomalous transport model and Chang-Hinton neoclassical model. For the plasma edge transport, two-dimensional transport equations are solved using the UEDGE code. Fluxes in the edge region use static diffusivity profiles based on an interpretive analysis of the experimental profiles. Simulations are used to study the range of validity of the selected models and sensitivity to neutral fueling. It has been demonstrated that the increase of neutral influx to the level that exceeds the level of neutral influx obtained from analysis simulations with the UEDGE code by a factor of two results in increased plasma density pedestal heights and plasma density levels in the scrape-off-layer region. However, the additional neutral influx has relatively weak effect on the pedestal width and plasma density profiles in the plasma core for the DIII-D discharge studied in this research. V
The CRONOS suite of codes for integrated tokamak modelling
Nuclear Fusion, 2010
CRONOS is a suite of numerical codes for the predictive/interpretative simulation of a full tokamak discharge. It integrates, in a modular structure, a 1D transport solver with general 2D magnetic equilibria, several heat, particle and impurities transport models, as well as heat, particle and momentum sources. This paper gives a first comprehensive description of the CRONOS suite: overall structure of the code, main available models, details on the simulation workflow and numerical implementation. Some examples of applications to the analysis of experimental discharges and the predictions of ITER scenarios are also given.
RITM-Code Modelling of Plasmas with Edge Transport Barrier
Contributions to Plasma Physics, 2006
Conditions for the formation of the edge transport barrier (ETB) in tokamaks are investigated by means of onedimensional transport modeling performed for the characteristic parameter range of the TEXTOR tokamak. The computations predict the formation of the ETB at the heating power given by the multi-machine scaling if the fraction of convective heat losses from the plasma does not exceed 50%. An increase of the amount of heat lost through convection above this critical value shifts the formation of ETB to a power several times above the level given by the scaling. For given plasma parameters, the ratio of the conductive to convective heat losses at the plasma edge is determined by the penetration of neutrals. By switching from a divertor to a limiter configuration when the distance between the LCMS and neutralizing plates decreases, this ratio increases due to the higher fraction of particles ionized inside the last closed magnetic surface (LCMS). This can be the reason for the higher H-mode power threshold in limiter tokamaks. First experimental results obtained in TEXTOR demonstrate a good agreement of the power required for ETB formation with the value calculated with 1.5D transport code RITM prior to the experiment.
Effect of the tokamak size in edge transport modelling and implications for DEMO
Journal of Nuclear Materials, 2007
The edge plasma of four devices, AUG, JET, ITER and a prototypical DEMO near ignition, is modelled with B2-EIRENE with a linear neutral model, carbon impurity, and variable throughput and scrape-off layer power. The scaling from ITER to DEMO is quantified as a power law scaling in device size, and JET and AUG simulations are compared to this scaling. Compared to ITER at the same scrape-off layer power per unit device volume and the same operating point relative to the edge-based density limit, edge helium density and peak power per unit area is found to be similar, and helium influx lower, for DEMO with impurity seeding. With a full neutral model, helium parameters are improved by a factor 3. Results of core modelling show that ignited operation of DEMO is possible with the impurity seeding required to render peak power loads compatible with a helium-cooled divertor.