Model-based estimation of tokamak plasma profiles and physics parameters: algorithm overview and application to ITER

Combining dynamic models and measurements into a consistent plasma state estimate is an important challenge for ITER and DEMO, due to the inherent limitations regarding diagnostic coverage in a nuclear fusion reactor environment. In this work, a model-based estimation algorithm is proposed to improv...

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Main Authors: S. Van Mulders, F. Felici, S.C. McIntosh, F. Carpanese, C.E. Contré, R. Coosemans, O. Kudláček, F. Pastore, S.D. Pinches, M. Reisner, O. Sauter
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:Nuclear Fusion
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Online Access:https://doi.org/10.1088/1741-4326/add16e
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author S. Van Mulders
F. Felici
S.C. McIntosh
F. Carpanese
C.E. Contré
R. Coosemans
O. Kudláček
F. Pastore
S.D. Pinches
M. Reisner
O. Sauter
author_facet S. Van Mulders
F. Felici
S.C. McIntosh
F. Carpanese
C.E. Contré
R. Coosemans
O. Kudláček
F. Pastore
S.D. Pinches
M. Reisner
O. Sauter
author_sort S. Van Mulders
collection DOAJ
description Combining dynamic models and measurements into a consistent plasma state estimate is an important challenge for ITER and DEMO, due to the inherent limitations regarding diagnostic coverage in a nuclear fusion reactor environment. In this work, a model-based estimation algorithm is proposed to improve real-time and post-shot estimation of tokamak plasma profiles. The RAPTOR rapid transport solver is employed as a dynamic state observer for the parallel current density $j_\mathrm {par}$ , the electron temperature $T_\mathrm e$ and the electron density $n_\mathrm e$ , applying an Extended Kalman Filter (EKF). The implementation of an EKF which, in addition to the plasma profiles, estimates model disturbances and model parameters has enabled us to account for systematic model-reality mismatches and provides an avenue to automatically validate simple transport models that are easily interpretable and machine-independent, based on raw experimental data. Estimates of transport model coefficients can be directly used to find adequate settings for launching a predictive simulation, accelerating inter-discharge scenario design. Furthermore, a method for maximum likelihood identification of model uncertainty statistics from a database of recorded measurement data is proposed. The RAPTOR EKF is tested for reconstruction of the $j_\mathrm {par}$ , $T_\mathrm e$ and $n_\mathrm e$ profile evolution for an ITER Q  = 10 plasma discharge, from ramp-up to ramp-down, based on synthetic Thomson scattering and boundary poloidal flux measurements, generated by adding realistic measurement noise to a DINA-JINTRAC simulation. This approach enables improved safety factor profile estimation in the absence of direct internal current density measurements.
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spelling doaj-art-cad03efcbd7649d48a18da689436e35c2025-08-20T03:48:57ZengIOP PublishingNuclear Fusion0029-55152025-01-0165606600610.1088/1741-4326/add16eModel-based estimation of tokamak plasma profiles and physics parameters: algorithm overview and application to ITERS. Van Mulders0https://orcid.org/0000-0003-3184-3361F. Felici1https://orcid.org/0000-0001-7585-376XS.C. McIntosh2F. Carpanese3C.E. Contré4R. Coosemans5https://orcid.org/0000-0001-8110-3156O. Kudláček6https://orcid.org/0009-0008-0356-115XF. Pastore7S.D. Pinches8https://orcid.org/0000-0003-0132-945XM. Reisner9O. Sauter10https://orcid.org/0000-0002-0099-6675ITER Organization , Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex, FranceÉcole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC) , CH-1015 Lausanne, SwitzerlandITER Organization , Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex, FranceÉcole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC) , CH-1015 Lausanne, SwitzerlandÉcole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC) , CH-1015 Lausanne, SwitzerlandÉcole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC) , CH-1015 Lausanne, SwitzerlandMax-Planck-Institut für Plasmaphysik , 85748 Garching bei München, GermanyÉcole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC) , CH-1015 Lausanne, SwitzerlandITER Organization , Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex, FranceMax-Planck-Institut für Plasmaphysik , 85748 Garching bei München, GermanyÉcole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC) , CH-1015 Lausanne, SwitzerlandCombining dynamic models and measurements into a consistent plasma state estimate is an important challenge for ITER and DEMO, due to the inherent limitations regarding diagnostic coverage in a nuclear fusion reactor environment. In this work, a model-based estimation algorithm is proposed to improve real-time and post-shot estimation of tokamak plasma profiles. The RAPTOR rapid transport solver is employed as a dynamic state observer for the parallel current density $j_\mathrm {par}$ , the electron temperature $T_\mathrm e$ and the electron density $n_\mathrm e$ , applying an Extended Kalman Filter (EKF). The implementation of an EKF which, in addition to the plasma profiles, estimates model disturbances and model parameters has enabled us to account for systematic model-reality mismatches and provides an avenue to automatically validate simple transport models that are easily interpretable and machine-independent, based on raw experimental data. Estimates of transport model coefficients can be directly used to find adequate settings for launching a predictive simulation, accelerating inter-discharge scenario design. Furthermore, a method for maximum likelihood identification of model uncertainty statistics from a database of recorded measurement data is proposed. The RAPTOR EKF is tested for reconstruction of the $j_\mathrm {par}$ , $T_\mathrm e$ and $n_\mathrm e$ profile evolution for an ITER Q  = 10 plasma discharge, from ramp-up to ramp-down, based on synthetic Thomson scattering and boundary poloidal flux measurements, generated by adding realistic measurement noise to a DINA-JINTRAC simulation. This approach enables improved safety factor profile estimation in the absence of direct internal current density measurements.https://doi.org/10.1088/1741-4326/add16eextended Kalman filterdata assimilationITERintegrated tokamak simulationparameter estimationreal-time control
spellingShingle S. Van Mulders
F. Felici
S.C. McIntosh
F. Carpanese
C.E. Contré
R. Coosemans
O. Kudláček
F. Pastore
S.D. Pinches
M. Reisner
O. Sauter
Model-based estimation of tokamak plasma profiles and physics parameters: algorithm overview and application to ITER
Nuclear Fusion
extended Kalman filter
data assimilation
ITER
integrated tokamak simulation
parameter estimation
real-time control
title Model-based estimation of tokamak plasma profiles and physics parameters: algorithm overview and application to ITER
title_full Model-based estimation of tokamak plasma profiles and physics parameters: algorithm overview and application to ITER
title_fullStr Model-based estimation of tokamak plasma profiles and physics parameters: algorithm overview and application to ITER
title_full_unstemmed Model-based estimation of tokamak plasma profiles and physics parameters: algorithm overview and application to ITER
title_short Model-based estimation of tokamak plasma profiles and physics parameters: algorithm overview and application to ITER
title_sort model based estimation of tokamak plasma profiles and physics parameters algorithm overview and application to iter
topic extended Kalman filter
data assimilation
ITER
integrated tokamak simulation
parameter estimation
real-time control
url https://doi.org/10.1088/1741-4326/add16e
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