Vertical instability forecasting and controllability assessment of multi-device tokamak plasmas in DECAF with data-driven optimization

Tobin, M.; Sabbagh, S. A.; Zamkovska, V.; Riquezes, J. D.; Butt, J.; Cunningham, G.; Kogan, L.; Measures, J.; Blackmore, S.; Ham, C.; Harrison, J.; Berkery, J. W.; Gerhardt, S.; Bak, J. G.; Lee, J.; Yoon, S. W.

doi:10.1088/1361-6587/ad7531

Title: Vertical instability forecasting and controllability assessment of multi-device tokamak plasmas in DECAF with data-driven optimization

Journal Article · 10 September 2024 · Plasma Physics and Controlled Fusion

DOI: https://doi.org/10.1088/1361-6587/ad7531 · OSTI ID:2440782

;

; Cunningham, G.; Kogan, L.; Measures, J.; Blackmore, S.;

;

; Gerhardt, S.;

; Lee, J.; Yoon, S. W.

Abstract Reliable vertical position control will be an essential element of any future tokamak-based fusion power plant in order to reduce disruptions and maximize performance. We investigate methods to improve vertical controllability boundary determination in plasma operational space and demonstrate a data-driven approach based on direct pseudoinversion of operational space data that is rigorously quantitative, applicable in real-time plasma control systems, and physically intuitive to interpret. Applied to historical shot data from entire run campaigns on the MAST-U, KSTAR, and NSTX tokamaks, this approach, implemented in DECAF, improves vertical displacement event identification accuracy to 98.9%–100%. Further, we explore the application of a physics-based vertical stability metric as an early warning forecaster for vertical displacement events. The development of a linear surrogate model for the plasma current density profile, with a coefficient of determination of 0.992 on the training dataset, enables potential employment of this forecaster in real-time. The application of this approach on historical data from the MAST-U MU02 campaign yields a forecaster with 62.6% accuracy, indicating promise for this method when further refined and potentially coupled with other stability metrics.

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Research Organization:: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: USDOE

Contributing Organization:: MAST Upgrade Team

Grant/Contract Number:: AC02-09CH11466; SC0018623; SC0020415; SC0021311

OSTI ID:: 2440782

Journal Information:: Plasma Physics and Controlled Fusion, Journal Name: Plasma Physics and Controlled Fusion Journal Issue: 10 Vol. 66; ISSN 0741-3335

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: United Kingdom

Language:: English

References (32)

National Spherical Torus Experiment: engineering overview and research results 1999–2000 Neumeyer, C. Fusion Engineering and Design, Vol. 56-57 https://doi.org/10.1016/S0920-3796(01)00411-2	journal	October 2001
Equilibrium reconstruction in an iron core tokamak using a deterministic magnetisation model Appel, L. C.; Lupelli, I. Computer Physics Communications, Vol. 223 https://doi.org/10.1016/j.cpc.2017.09.016	journal	February 2018
High performance plasma vertical position control system for upgraded MAST Cunningham, G. Fusion Engineering and Design, Vol. 88, Issue 12 https://doi.org/10.1016/j.fusengdes.2013.10.001	journal	December 2013
Improved fast vertical control in KSTAR Mueller, D.; Hahn, S. H.; Eidietis, N. Fusion Engineering and Design, Vol. 141 https://doi.org/10.1016/j.fusengdes.2019.02.046	journal	April 2019
Avoidance of vertical displacement events in DIII-D using a neural network growth rate estimator Sammuli, B. S.; Barr, J. L.; Humphreys, D. A. Fusion Engineering and Design, Vol. 169 https://doi.org/10.1016/j.fusengdes.2021.112492	journal	August 2021
MAST-upgrade divertor facility and assessing performance of long-legged divertors Fishpool, G.; Canik, J.; Cunningham, G. Journal of Nuclear Materials, Vol. 438 https://doi.org/10.1016/j.jnucmat.2013.01.067	journal	July 2013
A generalized inverse for matrices Penrose, R. Mathematical Proceedings of the Cambridge Philosophical Society, Vol. 51, Issue 3 https://doi.org/10.1017/S0305004100030401	journal	July 1955
Random Forests Breiman, Leo Machine Learning, Vol. 45, Issue 1, p. 5-32 https://doi.org/10.1023/A:1010933404324	journal	January 2001
Array programming with NumPy Harris, Charles R.; Millman, K. Jarrod; van der Walt, Stéfan J. Nature, Vol. 585, Issue 7825 https://doi.org/10.1038/s41586-020-2649-2	journal	September 2020
Theory of tokamak disruptions Boozer, Allen H. Physics of Plasmas, Vol. 19, Issue 5 https://doi.org/10.1063/1.3703327	journal	May 2012
Disruption event characterization and forecasting in tokamaks Sabbagh, S. A.; Berkery, J. W.; Park, Y. S. Physics of Plasmas, Vol. 30, Issue 3 https://doi.org/10.1063/5.0133825	journal	March 2023
Reconstruction of current profile parameters and plasma shapes in tokamaks Lao, L. L.; St. John, H.; Stambaugh, R. D. Nuclear Fusion, Vol. 25, Issue 11 https://doi.org/10.1088/0029-5515/25/11/007	journal	November 1985
Control of the vertical instability in tokamaks Lazarus, E. A.; Lister, J. B.; Neilson, G. H. Nuclear Fusion, Vol. 30, Issue 1 https://doi.org/10.1088/0029-5515/30/1/010	journal	January 1990
Real time equilibrium reconstruction for tokamak discharge control Ferron, J. R.; Walker, M. L.; Lao, L. L. Nuclear Fusion, Vol. 38, Issue 7 https://doi.org/10.1088/0029-5515/38/7/308	journal	July 1998
Chapter 1: Overview and summary Editors, ITER Physics Basis; Co-Chairs, ITER Physics Expert Group Chairs an; Unit, ITER Joint Central Team and Physics Nuclear Fusion, Vol. 39, Issue 12 https://doi.org/10.1088/0029-5515/39/12/301	journal	December 1999
Design and construction of the KSTAR tokamak Lee, G. S.; Kwon, M.; Doh, C. J. Nuclear Fusion, Vol. 41, Issue 10 https://doi.org/10.1088/0029-5515/41/10/318	journal	October 2001
Equilibrium properties of spherical torus plasmas in NSTX Sabbagh, S. A.; Kaye, S. M.; Menard, J. Nuclear Fusion, Vol. 41, Issue 11 https://doi.org/10.1088/0029-5515/41/11/309	journal	November 2001
The stability margin of elongated plasmas Portone, Alfredo Nuclear Fusion, Vol. 45, Issue 8 https://doi.org/10.1088/0029-5515/45/8/021	journal	August 2005
Plasma shape control on the National Spherical Torus Experiment (NSTX) using real-time equilibrium reconstruction Gates, D. A.; Ferron, J. R.; Bell, M. Nuclear Fusion, Vol. 46, Issue 1 https://doi.org/10.1088/0029-5515/46/1/002	journal	December 2005
Disruption scenarios, their mitigation and operation window in ITER Sugihara, M.; Shimada, M.; Fujieda, H. Nuclear Fusion, Vol. 47, Issue 4 https://doi.org/10.1088/0029-5515/47/4/012	journal	March 2007
Chapter 3: MHD stability, operational limits and disruptions Hender, T. C.; Wesley, J. C.; Bialek, J. Nuclear Fusion, Vol. 47, Issue 6 https://doi.org/10.1088/0029-5515/47/6/S03	journal	June 2007
Experimental vertical stability studies for ITER performance and design guidance Humphreys, D. A.; Casper, T. A.; Eidietis, N. Nuclear Fusion, Vol. 49, Issue 11 https://doi.org/10.1088/0029-5515/49/11/115003	journal	September 2009
Survey of disruption causes at JET de Vries, P. C.; Johnson, M. F.; Alper, B. Nuclear Fusion, Vol. 51, Issue 5 https://doi.org/10.1088/0029-5515/51/5/053018	journal	April 2011
Disruptions in tokamaks Schuller, F. C. Plasma Physics and Controlled Fusion, Vol. 37, Issue 11A https://doi.org/10.1088/0741-3335/37/11A/009	journal	November 1995
Non-linear instability at large vertical displacements in the MAST tokamak Windridge, M. J.; Cunningham, G.; Hender, T. C. Plasma Physics and Controlled Fusion, Vol. 53, Issue 3 https://doi.org/10.1088/0741-3335/53/3/035018	journal	February 2011
Development and experimental qualification of novel disruption prevention techniques on DIII-D Barr, J. L.; Sammuli, B.; Humphreys, D. A. Nuclear Fusion, Vol. 61, Issue 12 https://doi.org/10.1088/1741-4326/ac2d56	journal	October 2021
NSTX-U research advancing the physics of spherical tokamaks Berkery, John W.; Adebayo-Ige, Promise Oluwagbope; Al Khawaldeh, H. Nuclear Fusion https://doi.org/10.1088/1741-4326/ad3092	journal	March 2024
DECAF cross-device characterization of tokamak disruptions indicated by abnormalities in plasma vertical position and current Zamkovska, V.; Sabbagh, S. A.; Tobin, M. Nuclear Fusion, Vol. 64, Issue 6, p. 066030 https://doi.org/10.1088/1741-4326/ad3fca	journal	May 2024
The fourteenth western meeting of the American Mathematical Society Dresden, Arnold Bulletin of the American Mathematical Society, Vol. 26, Issue 9 https://doi.org/10.1090/S0002-9904-1920-03322-7	journal	January 1920
Matplotlib: A 2D Graphics Environment Hunter, John D. Computing in Science & Engineering, Vol. 9, Issue 3 https://doi.org/10.1109/MCSE.2007.55	journal	January 2007
A Theory of Adaptive Pattern Classifiers Amari, Shunichi IEEE Transactions on Electronic Computers, Vol. EC-16, Issue 3 https://doi.org/10.1109/PGEC.1967.264666	journal	June 1967
Passive Vertical Stability in the Next Generation Tokamaks Leuer, J. A. Fusion Technology, Vol. 15, Issue 2P2A https://doi.org/10.13182/FST89-A39747	journal	March 1989

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