1. Introduction to the EUROfusion Project Code Development for integrated modelling¶
The EUROfusion Project on Code Development for Integrated Modelling (WP-CD) supports the achievement of the European Fusion Roadmap at Horizon 2020 goals, via the development of existing modelling codes with a particular focus on integrated modelling. The primary objectives of WPCD are:
Provide a suite of codes that can be validated on existing Tokamaks and used for JT-60SA, ITER and DEMO predictions:
build on the existing modelling codes developed by the EUROfusion Consortium members including the Integrated Modelling (EU-IM) infrastructure, toolset and codes developed under the former EFDA ITM Task Force,
add new physics to the existing models
couple codes into integrated workflows
Specific ITER simulation work in support of ITER IO and F4E with specified deliverables.
WPCD operates under a work plan aiming to provide in the long term a full suite of integrated simulation workflows, incorporating core-edge-SOL/PFC coupling, first-principles models and control elements. A central task is the development of the modular European Transport Simulator, ETS, which is being deployed to JET and MST modelling infrastructures for validation and application to experimental analysis.
In addition to code and workflow development, rigorous code verification is also performed under WPCD, within the EU-IM framework; whereas validation of the released integrated modelling workflows against the experiments is performed under WPJET1 and WPMST1.
The Work Package is run as a project and managed by a project leader (M. Romanelli, UKAEA, firstname.lastname@example.org)
In 2019 the structure of the project has been reviewed and changed.
The project is now organised into three coordinated areas or subprojects reflecting the present priorities: Enabling Workflow Exploitation, Workflow Development, Workflow adaptation to IMAS. The Enabling Workflow Exploitation Area (EWE) will coordinate the development of pre-processing tools for the routine use of ETS and the equilibrium-MHD-stability workflow in EUROfusion facilities, the development of visualization tools, synthetic diagnostics and the provision of training to users. The Workflow Development Area or subproject will coordinate the continuous development of existing and new workflows in IMAS addressing specific modelling needs of the other EUROfusion work packages. The Workflow adaptation to IMAS Area will operate in strong collaboration with ITER IO and will ensure the complete adaptation of existing workflows to IMAS using the most updated Data Dictionary.
1.1. The European Integrated Modelling (EU-IM) approach¶
The choice of Integrated Modelling made by the former EFDA ITM and pursued now under EUROfusion WPCD is unique and original: it entails the development of a comprehensive and completely generic tokamak simulator including both the physics and the machine, which can be applied for any fusion device. The simulation platform was designed to be fully modular, flexible, and independent of a programming language.The choice of modularity implies that each module contains a single physical model and that the communication between the modules is standardised: a set of common common rules (ontology) clearly specify the format of the data to be consistently exchanged between modules (data-structure). The complexity of coupling the codes together is therefore transferred to the definition of a generic data-structure (allowing to describe and exchange information concerning both physical quantities and technical objects, not assuming the origin of those), extensible to allow the integration of new physics, as well as more elaborate machine geometries and experimental data in the future. A central project is the development of the so-called European Transport Simulator (ETS) aimed to meet all the EU-IM requirements, namely modularity, flexibility and standardized interfaces. In terms of the physics, the ETS is designed to solve the standard set of one-dimensional time dependent equations which describe the evolution of the core plasma. The solver itself is designed with a modular approach enabling the separation of the physics from the numerics, thereby facilitating the testing/usage of the numerical schemes that best suit a particular physical simulation.
The European Integrated Tokamak Modelling Task Force (ITM-TF) operated under EFDA from 2004 until 2013. The main mission of the ITM TF was to provide a software infrastructure framework for EU integrated modelling activities (EU-IM) as well as a validated suite of simulation codes for the modelling of present experiments, ITER and DEMO plasmas. The ITM TF operated until 2013 under a work programme formulated to support this goal, structuring the EU modelling effort around existing experiments and ITER scenario prediction while maintaining a long term strategic aim to provide a validated set of European modelling tools for ITER exploitation. The EU-IM effort was then pursued under the EUROfusion project WPCD, progressing towards the achievement of a main milestone, “Extended Core Transport simulator used for analysis of JET1 and MST1 campaigns and developing facilities”.
During the first phase of the EU-IM effort, surveys and cross-verification of the available European models and numerical codes were performed within the individual integrated modelling projects and the data-structure was extensively discussed and defined. Equilibrium, linear MHD stability, core transport and RF wave propagation, as well as the poloidal field systems and a few diagnostics were the first topics addressed. Data structures were finalised for these and then expanded to address, among others, non-linear MHD, edge physics, turbulence and neutral beam propagation. In parallel to the development of the physics concepts, the EU-IM effort developed the tools to manipulate the data structure and use it in fully flexible and modular simulation workflows. The EU-IM database contains machine descriptions from JET, Tore Supra, MAST, (as well as FTU, FAST), AUG, ITER, JT-60SA as well as some experimental data from Tore Supra (WEST) and JET. The EU-IM futher achieved the development of the first release version of a fully modular and versatile transport simulator, the ETS, with all the essential functionalities. The validation of the ETS simulator first started in 2010 against the state-of-the-art transport codes and ETS recently started to be used for the first physics applications. Next steps are the validation of the simulator for a complete discharge on existing experimental data with the available modules, the integration of more quantitative physics models (“ab-initio”) and the integration of the whole modelling of the device.
The main WPCD achievements are listed below: 1. An high-resolution equilibrium and linear MHD stability chain, for core and pedestal, applicable to peeling-ballooning type instabilities has been released for the analysis of equilibria from any tokamak integrated in the EU-IM platform, including ITER and DEMO. A predictive J-alpha MHD pedestal stability analysis workflow has also been developed and is in test release stage. 2. The fixed boundary core European Transport Simulator ETS, with various equilibrium modules and a full hierarchy of transport models, impurities, pellets, neutrals, sawteeth, Neoclassical Tearing Modes (NTM) modules, and full integration of Heating and Current Drive sources (Electron Cyclotron, Neutral Beam Injection, Ion Cyclotron, alpha), including synergies has been released.The released ETS workflow has been implemented in JET modelling infrastructure and went through validation. 3. A feedback controlled free boundary transport simulator prototype is operational and under verification. 4. A Scrape-Off-Layer (SOL) turbulence workflow including a synthetic probe, directly reading from experimental database has been developed and applied to analyse ASDEX-Upgrade divertor power deposition. 5. Benchmarks of EC, IC and NBI codes within the EU-IM infrastructure were carried out on identified test cases and presented in conference (Topical Conference on Radiofrequency Power in Plasmas, EPS, IAEA Technical Meeting on Energetic Particles (EP)). 7. Prototypes of self-consistent coupling between core and edge transport codes were demonstrated, in particular automated direct coupling of the ETS core transport code to the 2D edge transport code SOLPS. 8. SOLPS technical optimization studies (parareal algorithm, speed-up techniques, reduced physics models) provided an assessment of speed-up techniques to be possibly integrated in SOLPS-ITER. 9. A prototype acyclic workflow for modelling the SOL and interaction with Plasma Facing Components (PFC) was demonstrated by coupling the 2D transport code SOPLS to the 3D Monte Carlo PWI and impurity transport code ERO.
-G.L. Falchetto, et al., and the EUROfusion-IM Team, MULTI-MACHINE ANALYSIS OF EU EXPERIMENTS USING THE EUROFUSION INTEGRATED MODELLING (EU-IM) FRAMEWORK, P1.1081, 46th EPS conference, Milan, 2019.
-G.I. Pokol, et al., “Runaway electron modelling in the ETS self-consistent core transport simulator”, Nuclear Fusion 59, 076024 (2019). https://doi.org/10.1088/1741-4326/ab13da
-Y.-S. Na et al.,”On Benchmarking of Simulations of Particle Transport in ITER”, Nuclear Fusion 59 (7), 076026, 2019.
-A.H. Nielsen, et al. “Synthetic edge and SOL diagnostics - a bridge between experiments and theory”, THD/P7-4 IAEA CN-258 2018. https://conferences.iaea.org/indico/event/151/papers/5806/files/4686-Nielsen-THD-P7-4.pdf, Nuclear Fusion accepted
-R. Coelho, et al., “Plasma equilibrium reconstruction of JET discharges using the IMAS modelling infrastructure“, TH/P5-27, IAEA CN-258, 2018. https://conferences.iaea.org/indico/event/151/papers/6136/files/4812-Paper_IAEA_Coelho_v7.pdf
-P. Strand, et al., “Towards a predictive modelling capacity for DT plasmas: European Transport Simulator (ETS) verification and validation“, TH/P6-14, IAEA CN-258, 2018. https://conferences.iaea.org/indico/event/151/papers/5943/files/4801-IAEA_FEC18_THP6_14_Strand.pdf
-S. Nowak, et al., “Analysis and modelling of NTMs dynamics in JET discharges using the European Transport Simulator (ETS) and integrated modelling tools”, TH/P6-26, IAEA CN-258 2018. https://conferences.iaea.org/indico/event/151/papers/6039/files/4878-64930_snowak_iaea2018_paper_final_rev.pdf
-G.I. Pokol, et al., “Runaway electron modelling in the ETS self-consistent core transport simulator”, TH/P8-15, IAEA CN-258, 2018. https://conferences.iaea.org/indico/event/151/papers/6162/files/4621-Pokol_IAEA-FEC_2018-paper.pdf
-V. Basiuk, P. Huynh, A. Merle, S. Nowak, O. Sauter, “Towards self-consistent plasma modelisation in presence of neoclassical tearing mode and sawteeth: effects on transport coefficients”, Plasma Phys. Control. Fusion 59 (12), 125012 (2017) https://doi.org/10.1088/1361-6587/aa8c8c
-D. Samaddar, D.P. Coster, X. Bonnin, C. Bergmeister, E. Havlickova, L.A. Berry, W.R. Elwasif, D.B. Batchelor, “Temporal parallelization of edge plasma simulations using the parareal algorithm and the SOLPS code”, Computer Physics Communications 221, 19-27 (2017). https://doi.org/10.1016/j.cpc.2017.07.012
-M. Baelmans, P. Borner, K. Ghoos, G. Samaey, “Efficient code simulation strategies for B2-EIRENE”, Nuclear Materials and Energy 12, 858-863 (2017) https://doi.org/10.1016/j.nme.2016.10.028
-D.P. Coster, “Exploring the edge operating space of fusion reactors using reduced physics models”, Nuclear Materials and Energy 12, 1055-1060 (2017) https://doi.org/10.1016/j.nme.2016.12.033
-G.L. Falchetto, et al., and the EUROfusion-IM Team, “EUROfusion Integrated Modelling (EU-IM) capabilities and selected physics applications”, Proc. 26th IAEA Fusion Energy Conference, Kyoto, Japan, IAEA CN-234, TH/ P2-13, 2016. https://nucleus.iaea.org/sites/fusionportal/Shared%20Documents/FEC%202016/fec2016-preprints/preprint0362.pdf
-Y.-S. Na et al., “On Benchmarking of Simulations of Particle Transport in ITER”, Proc. 26th IAEA Fusion Energy Conference, Kyoto, Japan, TH/P2-24, IAEA CN-234, 2016.
-G.L. Falchetto, et al.,and ITM-TF contributors, “The European Integrated Tokamak Modelling (ITM) effort: achievements and first physics results”, Nuclear Fusion 54, 043018, 2014.
-D. Kalupin et al, “Numerical analysis of JET discharges with the European Transport Simulator”, Nucl. Fusion 53, 123007, 2013.
-D. Penko “3D tokamak Wall description within ITER Integrated Modelling and Analysis (IMAS) framework“, Proc. 45th European Physical Society Conference on Plasma Physics (EPS), 2018.
-O. Asunta, R. Coelho, D. Kalupin, T. Johnson, T. Franke and EU-IM Team, “Predictions of neutral beam current drive in DEMO using BBNBI and ASCOT within the European Transport Simulator”, 42nd EPS 2015, P2.156 ECA Vol. 39E ISBN 2-914771-98-3.
-R. Bilato, N. Bertelli, M. Brambilla, R. Dumont, E.F. Jaeger, T. Johnson, E. Lerche, O. Sauter, D. Van Eester and L. Villard, “Status of the benchmark activity of ICRF full-wave codes within EUROfusion WPCD and beyond”, 21st Topical Conference on Radiofrequency Power in Plasmas, 2015.
Some posters describing the ITM-TF achievements were presented in an “ITM EXPO” at the 2011 EPS fusion conference in Strasbourg.
The EUROfusion-IM Team members are defined in the link: http://euro-fusionscipub.org/eu-im
ITM-TF contributors were defined in the Appendix of G.L. Falchetto et al., Nuclear Fusion 54,043018, 2014. This list reproduces the status of of members in 2012 and is not exhaustive. A grateful thank you to all those who contributed and promoted EU-IM since its beginnigs.
Collaborative Development Environment (CDE) A collaborative development environment (CDE) is an online meeting space where a software development project’s stakeholders can work together, no matter what timezone or region they are in, to discuss, document , and produce project deliverables. The name was coined by Grady Booch.
- Consistent Physical Object (CPO)
A Consistent Physical Object (CPO) is a physics based, hierarchical data structure employed by the EU-IM for a complete description of a physics area, e.g. equilibrium. All EU-IM code modules interact through the exchange of CPOs. The CPOs also form the basic block of data written to the EU-IM database.
- Content Management System (CMS)
A content management system (CMS) is the collection of procedures used to manage work flow in a collaborative environment. These procedures can be manual or computer-based. The procedures are designed to:
Allow for a large number of people to contribute to and share stored data
Control access to data, based on user roles. User roles define what information each user can view or edit
Aid in easy storage and retrieval of data
Reduce repetitive duplicate input
Improve the ease of report writing
Improve communication between usersq
In a CMS, data can be defined as nearly anything - documents, movies, pictures, phone numbers, scientific data, etc. CMSs are frequently used for storing, controlling, revising, semantically enriching, and publishing documentation.
FC2K is a tool for wrapping a Fortran or C++ source code into a Kepler actor. Before using it, your physics code should be EU-IM-compliant (i.e. use CPOs as input/output).
Gforge hosts all projects (software and infrastructure) under the EU-IM.
- EUROfusion Gateway
The EUROfusion Gateway is a computer cluster presently hosted at CINECA, Bologna, Italy. It is used as central repository of the EU-IM software, as well as platfrom for developments and fusion simulations.
- EU-IM Portal
The EU-IM Portal is the web portal for the EU-IM, i.e. it hosts the EU-IM web pages and projects under Gforge.
- Universal Access Layer (UAL)
The UAL (Universal Access Layer) is a multi-language library that allows exchanging Consistent Physical Objects (CPOs) between various modules, and to write to an EU-IM database.
Modular element within a Kepler scientific workflow. Actors take execution instructions from a director. In other words, actors specify what processing occurs while the director specifies when it occurs. In the EU-IM Kepler workflows, most actors are modules which contain physics codes.
The process of adjusting numerical or physical modelling parameters in the computational model for the purpose of improving agreement with experimental data.
- data mapping
An XML file containing all the mapping essentials for mapping from a local experimental database for a specific tokamak device to the EU-IM database. The mapping essentials include for instance the download method, local signal names, gains and offsets, time base, and eventual interpolation option to ensure that only one time base is set for each CPO that is built from multiple local signals. A java code (exp2ITM developed under ISIP), with the MD and DM files as inputs, is then run to connect to the local device database, retrieve the required experimental data and populate the EU-IM database instance for that shot/device and dataversion.
A director controls (or directs) the execution of a workflow, just as a film director oversees a cast and crew.
A recognisable deficiency in any phase or activity of modelling and simulation that is not due to lack of knowledge.
Kepler is a software application for the analysis and modeling of scientific data. Kepler simplifies the effort required to create executable models by using a visual representation of these processes. These representations, or “scientific workflows”, display the flow of data among discrete analysis and modeling components.
- machine description
The machine description (MD) of a device builds on the set of engineering and diagnostic settings characterising a tokamak device. This includes, for instance, the vessel/limiter description, the PF coils and circuiting and lines of sight of diagnostics. In practice, all MD information is encapsulated in an XML file that emanates from the MD tagged datastructure schemas. An MD instance of a given device is then stored into the EU-IM database as shot 0 for that device database.
A representation of a physical system or process intended to enhance our ability to understand, predict, or control its behaviour.
A conceptual model consists of the observations, mathematical modelling data, and mathematical (e.g., partial differential) equations that describe the physical system. It will also include initial and boundary conditions.
The computational model is the computer program or code that implements the conceptual model. It includes the algorithms and iterative strategies. Parameters for the computational model include the number of grid points, algorithm inputs, and similar parameters, etc.
The process of construction or modification of a model
Use of a model to foretell the state of a physical system under conditions for which the model has not been validated.
The exercise or use of a model.
A potential deficiency in any phase or activity of the modelling process that is due to the lack of knowledge.
The process of determining the degree to which a model is an accurate representation of the real world form the perspective of the intended uses of the model.
The process of determining that a model implementation accurately represents the developer’s conceptual description of the model and the solution to the model.