Flexible, integrated modeling of tokamak stability, transport, equilibrium, and pedestal physics

B. C. Lyons; J. McClenaghan; T. Slendebroek; O. Meneghini; T. F. Neiser; S. P. Smith; D. B. Weisberg; E. A. Belli; J. Candy; J. M. Hanson; L. L. Lao; N. C. Logan; S. Saarelma; O. Sauter; P. B. Snyder; G. M. Staebler; K. E. Thome; A. D. Turnbull

doi:10.1063/5.0156877

Flexible, integrated modeling of tokamak stability, transport, equilibrium, and pedestal physics

B. C. Lyons, J. McClenaghan, T. Slendebroek, O. Meneghini, T. F. Neiser, S. P. Smith, D. B. Weisberg, E. A. Belli, J. Candy, J. M. Hanson, L. L. Lao, N. C. Logan, S. Saarelma, O. Sauter, P. B. Snyder, G. M. Staebler, K. E. Thome, A. D. Turnbull

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Abstract

The STEP (Stability, Transport, Equilibrium, and Pedestal) integrated-modeling tool has been developed in OMFIT to predict stable, tokamak equilibria self-consistently with core-transport and pedestal calculations. STEP couples theory-based codes to integrate a variety of physics, including magnetohydrodynamic stability, transport, equilibrium, pedestal formation, and current-drive, heating, and fueling. The input/output of each code is interfaced with a centralized ITER-Integrated Modelling & Analysis Suite data structure, allowing codes to be run in any order and enabling open-loop, feedback, and optimization workflows. This paradigm simplifies the integration of new codes, making STEP highly extensible. STEP has been verified against a published benchmark of six different integrated models. Core-pedestal calculations with STEP have been successfully validated against individual DIII-D H-mode discharges and across more than 500 discharges of the H 98 , y 2 database, with a mean error in confinement time from experiment less than 19%. STEP has also reproduced results in less conventional DIII-D scenarios, including negative-central-shear and negative-triangularity plasmas. Predictive STEP modeling has been used to assess performance in several tokamak reactors. Simulations of a high-field, large-aspect-ratio reactor show significantly lower fusion power than predicted by a zero-dimensional study, demonstrating the limitations of scaling-law extrapolations. STEP predictions have found promising scenarios for an EXhaust and Confinement Integration Tokamak Experiment, including a high-pressure, 80%-bootstrap-fraction plasma. ITER modeling with STEP has shown that pellet fueling enhances fusion gain in both the baseline and advanced-inductive scenarios. Finally, STEP predictions for the SPARC baseline scenario are in good agreement with published results from the physics basis.

Original language	English
Article number	092510
Journal	Physics of Plasmas
Volume	30
Issue number	9
DOIs	https://doi.org/10.1063/5.0156877
State	Published - Sep 1 2023
Externally published	Yes

Funding

This material was based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Award Nos. DE-FG02-95ER54309, DE-FC02-04ER54698, and DE-SC0017992. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231. This study was supported by General Atomics corporate funding. Contributions from O. Sauter were supported, in part, by the Swiss National Science Foundation.

Funders	Funder number
U.S. Department of Energy
Office of Science	DE-AC02-05CH11231, DE-FC02-04ER54698, DE-SC0017992, DE-FG02-95ER54309
Fusion Energy Sciences
General Atomics
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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Lyons, B. C., McClenaghan, J., Slendebroek, T., Meneghini, O., Neiser, T. F., Smith, S. P., Weisberg, D. B., Belli, E. A., Candy, J., Hanson, J. M., Lao, L. L., Logan, N. C., Saarelma, S., Sauter, O., Snyder, P. B., Staebler, G. M., Thome, K. E., & Turnbull, A. D. (2023). Flexible, integrated modeling of tokamak stability, transport, equilibrium, and pedestal physics. Physics of Plasmas, 30(9), Article 092510. https://doi.org/10.1063/5.0156877

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title = "Flexible, integrated modeling of tokamak stability, transport, equilibrium, and pedestal physics",

abstract = "The STEP (Stability, Transport, Equilibrium, and Pedestal) integrated-modeling tool has been developed in OMFIT to predict stable, tokamak equilibria self-consistently with core-transport and pedestal calculations. STEP couples theory-based codes to integrate a variety of physics, including magnetohydrodynamic stability, transport, equilibrium, pedestal formation, and current-drive, heating, and fueling. The input/output of each code is interfaced with a centralized ITER-Integrated Modelling & Analysis Suite data structure, allowing codes to be run in any order and enabling open-loop, feedback, and optimization workflows. This paradigm simplifies the integration of new codes, making STEP highly extensible. STEP has been verified against a published benchmark of six different integrated models. Core-pedestal calculations with STEP have been successfully validated against individual DIII-D H-mode discharges and across more than 500 discharges of the H 98 , y 2 database, with a mean error in confinement time from experiment less than 19%. STEP has also reproduced results in less conventional DIII-D scenarios, including negative-central-shear and negative-triangularity plasmas. Predictive STEP modeling has been used to assess performance in several tokamak reactors. Simulations of a high-field, large-aspect-ratio reactor show significantly lower fusion power than predicted by a zero-dimensional study, demonstrating the limitations of scaling-law extrapolations. STEP predictions have found promising scenarios for an EXhaust and Confinement Integration Tokamak Experiment, including a high-pressure, 80%-bootstrap-fraction plasma. ITER modeling with STEP has shown that pellet fueling enhances fusion gain in both the baseline and advanced-inductive scenarios. Finally, STEP predictions for the SPARC baseline scenario are in good agreement with published results from the physics basis.",

author = "Lyons, {B. C.} and J. McClenaghan and T. Slendebroek and O. Meneghini and Neiser, {T. F.} and Smith, {S. P.} and Weisberg, {D. B.} and Belli, {E. A.} and J. Candy and Hanson, {J. M.} and Lao, {L. L.} and Logan, {N. C.} and S. Saarelma and O. Sauter and Snyder, {P. B.} and Staebler, {G. M.} and Thome, {K. E.} and Turnbull, {A. D.}",

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Lyons, BC, McClenaghan, J, Slendebroek, T, Meneghini, O, Neiser, TF, Smith, SP, Weisberg, DB, Belli, EA, Candy, J, Hanson, JM, Lao, LL, Logan, NC, Saarelma, S, Sauter, O, Snyder, PB, Staebler, GM, Thome, KE & Turnbull, AD 2023, 'Flexible, integrated modeling of tokamak stability, transport, equilibrium, and pedestal physics', Physics of Plasmas, vol. 30, no. 9, 092510. https://doi.org/10.1063/5.0156877

TY - JOUR

T1 - Flexible, integrated modeling of tokamak stability, transport, equilibrium, and pedestal physics

AU - Lyons, B. C.

AU - McClenaghan, J.

AU - Slendebroek, T.

AU - Meneghini, O.

AU - Neiser, T. F.

AU - Smith, S. P.

AU - Weisberg, D. B.

AU - Belli, E. A.

AU - Candy, J.

AU - Hanson, J. M.

AU - Lao, L. L.

AU - Logan, N. C.

AU - Saarelma, S.

AU - Sauter, O.

AU - Snyder, P. B.

AU - Staebler, G. M.

AU - Thome, K. E.

AU - Turnbull, A. D.

PY - 2023/9/1

Y1 - 2023/9/1

N2 - The STEP (Stability, Transport, Equilibrium, and Pedestal) integrated-modeling tool has been developed in OMFIT to predict stable, tokamak equilibria self-consistently with core-transport and pedestal calculations. STEP couples theory-based codes to integrate a variety of physics, including magnetohydrodynamic stability, transport, equilibrium, pedestal formation, and current-drive, heating, and fueling. The input/output of each code is interfaced with a centralized ITER-Integrated Modelling & Analysis Suite data structure, allowing codes to be run in any order and enabling open-loop, feedback, and optimization workflows. This paradigm simplifies the integration of new codes, making STEP highly extensible. STEP has been verified against a published benchmark of six different integrated models. Core-pedestal calculations with STEP have been successfully validated against individual DIII-D H-mode discharges and across more than 500 discharges of the H 98 , y 2 database, with a mean error in confinement time from experiment less than 19%. STEP has also reproduced results in less conventional DIII-D scenarios, including negative-central-shear and negative-triangularity plasmas. Predictive STEP modeling has been used to assess performance in several tokamak reactors. Simulations of a high-field, large-aspect-ratio reactor show significantly lower fusion power than predicted by a zero-dimensional study, demonstrating the limitations of scaling-law extrapolations. STEP predictions have found promising scenarios for an EXhaust and Confinement Integration Tokamak Experiment, including a high-pressure, 80%-bootstrap-fraction plasma. ITER modeling with STEP has shown that pellet fueling enhances fusion gain in both the baseline and advanced-inductive scenarios. Finally, STEP predictions for the SPARC baseline scenario are in good agreement with published results from the physics basis.

AB - The STEP (Stability, Transport, Equilibrium, and Pedestal) integrated-modeling tool has been developed in OMFIT to predict stable, tokamak equilibria self-consistently with core-transport and pedestal calculations. STEP couples theory-based codes to integrate a variety of physics, including magnetohydrodynamic stability, transport, equilibrium, pedestal formation, and current-drive, heating, and fueling. The input/output of each code is interfaced with a centralized ITER-Integrated Modelling & Analysis Suite data structure, allowing codes to be run in any order and enabling open-loop, feedback, and optimization workflows. This paradigm simplifies the integration of new codes, making STEP highly extensible. STEP has been verified against a published benchmark of six different integrated models. Core-pedestal calculations with STEP have been successfully validated against individual DIII-D H-mode discharges and across more than 500 discharges of the H 98 , y 2 database, with a mean error in confinement time from experiment less than 19%. STEP has also reproduced results in less conventional DIII-D scenarios, including negative-central-shear and negative-triangularity plasmas. Predictive STEP modeling has been used to assess performance in several tokamak reactors. Simulations of a high-field, large-aspect-ratio reactor show significantly lower fusion power than predicted by a zero-dimensional study, demonstrating the limitations of scaling-law extrapolations. STEP predictions have found promising scenarios for an EXhaust and Confinement Integration Tokamak Experiment, including a high-pressure, 80%-bootstrap-fraction plasma. ITER modeling with STEP has shown that pellet fueling enhances fusion gain in both the baseline and advanced-inductive scenarios. Finally, STEP predictions for the SPARC baseline scenario are in good agreement with published results from the physics basis.

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DO - 10.1063/5.0156877

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Flexible, integrated modeling of tokamak stability, transport, equilibrium, and pedestal physics

Abstract

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