Density limits as disruption forecasters for spherical tokamaks

Berkery, John W.; Sabbagh, Steve A.; Ham, Christopher J.; Zamkovska, Veronika; Butt, Jalal; Riquezes, Juan; Tobin, Matthew; Henderson, Stuart Scott; Kogan, Lucy; Patel, Bhavin S.; Scannell, Rory; Trier, Elisee; LeBlanc, Benoit P.

doi:10.1088/1361-6587/ace476

Density limits as disruption forecasters for spherical tokamaks

Journal Article · Fri Jul 21 00:00:00 EDT 2023 · Plasma Physics and Controlled Fusion

DOI:https://doi.org/10.1088/1361-6587/ace476· OSTI ID:1992108

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Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Columbia Univ., New York, NY (United States)
UK Atomic Energy Authority (UKAEA), Culham (United Kingdom)

Fusion power output from spherical tokamaks would benefit from increased confined plasma density, but there exists a limit on the density before confinement is lost and the plasma current is disrupted. This density limit has long been characterized by a simple, global Greenwald limit proportional to the plasma current and inversely proportional to the cross sectional area of the plasma. It is shown that in the database of discharges from the National Spherical Tokamak Experiment (NSTX) and Mega Ampere Spherical Tokamak (MAST) spherical tokamaks, the likelihood of disruption does increase above the Greenwald limit, and especially in the plasma current rampdown phase. The physics of the density limit has been recently theoretically explored through local criteria. Several of these are tested using the disruption event characterization and forecasting (DECAF^TM) code for their potential effectiveness as disruption warning signals. For a limited set of NSTX discharges, a local island power balance criteria was found to be less reliable, presently, than the Greenwald limit. For this work, an empirical critical edge line density and a boundary turbulent transport limit were both tested for MAST-U, which has an electron density profile measurement with high spatial resolution in the outer part of the plasma. Both were found to have similar dependencies on key plasma parameters. In a limited set of MAST-U discharges that appear to disrupt due to rising density at values under the Greenwald limit, crossing of the boundary turbulent transport limit occurred close to the time of disruption. Finally, these limits were evaluated for their potential use in real-time, and it was found that with the necessary real-time inputs and with refinement through further testing, these limits could be implemented in a real-time disruption forecasting system.

View Accepted Manuscript (DOE)

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

Sponsoring Organization:: USDOE Office of Science (SC)

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

OSTI ID:: 1992108

Journal Information:: Plasma Physics and Controlled Fusion, Journal Name: Plasma Physics and Controlled Fusion Journal Issue: 9 Vol. 65; ISSN 0741-3335

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (73)

Density Limits as Disruption Forecasters for Spherical Tokamaks Berkery, John Princeton Plasma Physics Laboratory, Princeton University https://doi.org/10.34770/67tb-0988	dataset	January 2023
Review of MARFE phenomena in tokamaks Lipschultz, B. Journal of Nuclear Materials, Vol. 145-147 https://doi.org/10.1016/0022-3115(87)90306-0	journal	February 1987
Control-oriented modeling of the plasma particle density in tokamaks and application to real-time density profile reconstruction Blanken, T. C.; Felici, F.; Rapson, C. J. Fusion Engineering and Design, Vol. 126 https://doi.org/10.1016/j.fusengdes.2017.11.006	journal	January 2018
Use of virtual actuators in ASDEX Upgrade control Kudláček, O.; Treutterer, W.; Sieglin, B. Fusion Engineering and Design, Vol. 159 https://doi.org/10.1016/j.fusengdes.2020.111735	journal	October 2020
Rapid prototyping of advanced control schemes in ASDEX Upgrade Sieglin, B.; Maraschek, M.; Kudlacek, O. Fusion Engineering and Design, Vol. 161 https://doi.org/10.1016/j.fusengdes.2020.111958	journal	December 2020
Dynamic pulse scheduling in ASDEX Upgrade: Disruption avoidance and investigation of the H-Mode density limit Sieglin, B.; Maraschek, M.; Gude, A. Fusion Engineering and Design, Vol. 191 https://doi.org/10.1016/j.fusengdes.2023.113546	journal	June 2023
Model-based electron density estimation using multiple diagnostics on TCV Pastore, F.; Felici, F.; Bosman, T. O. S. J. Fusion Engineering and Design, Vol. 192 https://doi.org/10.1016/j.fusengdes.2023.113615	journal	July 2023
Impact of W events and dust on JET-ILW operation Sertoli, M.; Flanagan, J. C.; Bacharis, M. Journal of Nuclear Materials, Vol. 463 https://doi.org/10.1016/j.jnucmat.2014.12.033	journal	August 2015
Initial physics results from the National Spherical Torus Experiment Kaye, S. M.; Bell, M. G.; Bell, R. E. Physics of Plasmas, Vol. 8, Issue 5 https://doi.org/10.1063/1.1343089	journal	May 2001
Parametric dependence of density limits in the Tokamak Experiment for Technology Oriented Research (TEXTOR): Comparison of thermal instability theory with experiment Kelly, F. A.; Stacey, W. M.; Rapp, J. Physics of Plasmas, Vol. 8, Issue 11 https://doi.org/10.1063/1.1409958	journal	November 2001
A 130 point Nd:YAG Thomson scattering diagnostic on MAST Scannell, R.; Walsh, M. J.; Dunstan, M. R. Review of Scientific Instruments, Vol. 81, Issue 10 https://doi.org/10.1063/1.3460628	journal	October 2010
High-resolution tangential absolute extreme ultraviolet arrays for radiated power density measurements on NSTX-U Delgado-Aparicio, L.; Bell, R. E.; Faust, I. Review of Scientific Instruments, Vol. 85, Issue 11 https://doi.org/10.1063/1.4894835	journal	September 2014
A reduced resistive wall mode kinetic stability model for disruption forecasting Berkery, J. W.; Sabbagh, S. A.; Bell, R. E. Physics of Plasmas, Vol. 24, Issue 5 https://doi.org/10.1063/1.4977464	journal	May 2017
Density limits in tokamaks Stacey, W. M. Physics of Plasmas, Vol. 4, Issue 4 https://doi.org/10.1063/1.872194	journal	April 1997
Magneto-hydro-dynamic limits in spherical tokamaks Hender, T. C.; Allfrey, S. J.; Akers, R. Physics of Plasmas, Vol. 6, Issue 5 https://doi.org/10.1063/1.873493	journal	May 1999
Overview and first measurements of the MAST Upgrade bolometer diagnostic Lovell, J.; Reinke, M. L.; Field, A. R. Review of Scientific Instruments, Vol. 94, Issue 2 https://doi.org/10.1063/5.0128750	journal	February 2023
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
Some observations on maximum densities in tokamak experiments Murakami, M.; Callen, J. D.; Berry, L. A. Nuclear Fusion, Vol. 16, Issue 2 https://doi.org/10.1088/0029-5515/16/2/020	journal	April 1976
Transport in tokamaks – a review of experiment Hugill, J. Nuclear Fusion, Vol. 23, Issue 3 https://doi.org/10.1088/0029-5515/23/3/006	journal	March 1983
A new look at density limits in tokamaks Greenwald, M.; Terry, J. L.; Wolfe, S. M. Nuclear Fusion, Vol. 28, Issue 12 https://doi.org/10.1088/0029-5515/28/12/009	journal	December 1988
Transition to the second region of ideal MHD stability Sabbagh, S. A.; Hughes, M. H.; Phillips, M. W. Nuclear Fusion, Vol. 29, Issue 3 https://doi.org/10.1088/0029-5515/29/3/006	journal	March 1989
Simulations of deuterium-tritium experiments in TFTR Budny, R. V.; Bell, M. G.; Biglari, H. Nuclear Fusion, Vol. 32, Issue 3 https://doi.org/10.1088/0029-5515/32/3/I07	journal	March 1992
Density limit investigations on ASDEX Stabler, A.; McCormick, K.; Mertens, V. Nuclear Fusion, Vol. 32, Issue 9 https://doi.org/10.1088/0029-5515/32/9/I05	journal	September 1992
Chapter 2: Plasma confinement and transport Transport, ITER Physics Expert Group on Confin; Database, ITER Physics Expert Group on Confin; Editors, ITER Physics Basis Nuclear Fusion, Vol. 39, Issue 12 https://doi.org/10.1088/0029-5515/39/12/302	journal	December 1999
Exploration of spherical torus physics in the NSTX device Ono, M.; Kaye, S. M.; Peng, Y. -K. M. Nuclear Fusion, Vol. 40, Issue 3Y https://doi.org/10.1088/0029-5515/40/3Y/316	journal	March 2000
First results from MAST Sykes, A.; Akers, R. J.; Appel, L. C. Nuclear Fusion, Vol. 41, Issue 10 https://doi.org/10.1088/0029-5515/41/10/310	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
Prediction of density limit disruption boundaries from diagnostic signals using neural networks Sengupta, A.; Ranjan, P. Nuclear Fusion, Vol. 41, Issue 5 https://doi.org/10.1088/0029-5515/41/5/302	journal	May 2001
Chapter 2: Plasma confinement and transport Physics), E. J. Doyle (Chair Transport; Modelling), W. A. Houlberg (Chair Confinement Da; Edge), Y. Kamada (Chair Pedestal and Nuclear Fusion, Vol. 47, Issue 6 https://doi.org/10.1088/0029-5515/47/6/S02	journal	June 2007
Statistical analysis of disruptions in JET de Vries, P. C.; Johnson, M. F.; Segui, I. Nuclear Fusion, Vol. 49, Issue 5 https://doi.org/10.1088/0029-5515/49/5/055011	journal	April 2009
Overview of the physics and engineering design of NSTX upgrade Menard, J. E.; Gerhardt, S.; Bell, M. Nuclear Fusion, Vol. 52, Issue 8 https://doi.org/10.1088/0029-5515/52/8/083015	journal	July 2012
Disruptions, disruptivity and safer operating windows in the high- β spherical torus NSTX Gerhardt, S. P.; Bell, R. E.; Diallo, A. Nuclear Fusion, Vol. 53, Issue 4 https://doi.org/10.1088/0029-5515/53/4/043020	journal	April 2013
Detection of disruptions in the high- β spherical torus NSTX Gerhardt, S. P.; Darrow, D. S.; Bell, R. E. Nuclear Fusion, Vol. 53, Issue 6 https://doi.org/10.1088/0029-5515/53/6/063021	journal	May 2013
Investigation of MHD instabilities and control in KSTAR preparing for high beta operation Park, Y. S.; Sabbagh, S. A.; Bialek, J. M. Nuclear Fusion, Vol. 53, Issue 8 https://doi.org/10.1088/0029-5515/53/8/083029	journal	July 2013
Modifications to ideal stability by kinetic effects in NSTX Berkery, J. W.; Sabbagh, S. A.; Bell, R. E. Nuclear Fusion, Vol. 55, Issue 12 https://doi.org/10.1088/0029-5515/55/12/123007	journal	October 2015
A predictive model for the tokamak density limit Teng, Q.; Brennan, D. P.; Delgado-Aparicio, L. Nuclear Fusion, Vol. 56, Issue 10 https://doi.org/10.1088/0029-5515/56/10/106001	journal	July 2016
Density limits in toroidal plasmas Greenwald, Martin Plasma Physics and Controlled Fusion, Vol. 44, Issue 8 https://doi.org/10.1088/0741-3335/44/8/201	journal	July 2002
Scaling of the scrape-off layer width during inter-ELM H modes on MAST as measured by infrared thermography Thornton, A. J.; Kirk, A. Plasma Physics and Controlled Fusion, Vol. 56, Issue 5 https://doi.org/10.1088/0741-3335/56/5/055008	journal	April 2014
The H-mode density limit in the full tungsten ASDEX Upgrade tokamak Bernert, M.; Eich, T.; Kallenbach, A. Plasma Physics and Controlled Fusion, Vol. 57, Issue 1 https://doi.org/10.1088/0741-3335/57/1/014038	journal	November 2014
The operation region and MHD modes on the J-TEXT tokamak Huang, Mingxiang; Hu, Qiming; Shi, Peng Plasma Physics and Controlled Fusion, Vol. 58, Issue 12 https://doi.org/10.1088/0741-3335/58/12/125002	journal	October 2016
Path-oriented early reaction to approaching disruptions in ASDEX Upgrade and TCV in view of the future needs for ITER and DEMO Maraschek, M.; Gude, A.; Igochine, V. Plasma Physics and Controlled Fusion, Vol. 60, Issue 1 https://doi.org/10.1088/1361-6587/aa8d05	journal	November 2017
Validation of a tearing mode locking model using a database of disruptive plasmas at ASDEX Upgrade Klevarová, V.; Zohm, H.; Pautasso, G. Plasma Physics and Controlled Fusion, Vol. 62, Issue 2 https://doi.org/10.1088/1361-6587/ab5c41	journal	December 2019
Operational space and performance limiting events in the first physics campaign of MAST-U Berkery, J. W.; Sabbagh, S. A.; Kogan, L. Plasma Physics and Controlled Fusion, Vol. 65, Issue 4 https://doi.org/10.1088/1361-6587/acb464	journal	February 2023
Overview of NSTX Upgrade initial results and modelling highlights Menard, J. E.; Allain, J. P.; Battaglia, D. J. Nuclear Fusion, Vol. 57, Issue 10, Article No. 102006 https://doi.org/10.1088/1741-4326/aa600a	journal	June 2017
Multi-machine analysis of termination scenarios with comparison to simulations of controlled shutdown of ITER discharges de Vries, P. C.; Luce, T. C.; Bae, Y. S. Nuclear Fusion, Vol. 58, Issue 2 https://doi.org/10.1088/1741-4326/aa9c4c	journal	December 2017
Feedback controlled, reactor relevant, high-density, high-confinement scenarios at ASDEX Upgrade Lang, P. T.; Blanken, T. C.; Dunne, M. Nuclear Fusion, Vol. 58, Issue 3 https://doi.org/10.1088/1741-4326/aaa339	journal	January 2018
Correlation of the tokamak H-mode density limit with ballooning stability at the separatrix Eich, T.; Goldston, R. J.; Kallenbach, A. Nuclear Fusion, Vol. 58, Issue 3 https://doi.org/10.1088/1741-4326/aaa340	journal	January 2018
Hybrid neural network for density limit disruption prediction and avoidance on J-TEXT tokamak Zheng, W.; Hu, F. R.; Zhang, M. Nuclear Fusion, Vol. 58, Issue 5 https://doi.org/10.1088/1741-4326/aaad17	journal	March 2018
Real-time plasma state monitoring and supervisory control on TCV Blanken, T. C.; Felici, F.; Galperti, C. Nuclear Fusion, Vol. 59, Issue 2 https://doi.org/10.1088/1741-4326/aaf451	journal	January 2019
NSTX/NSTX-U theory, modeling and analysis results Kaye, S. M.; Battaglia, D. J.; Baver, D. Nuclear Fusion, Vol. 59, Issue 11 https://doi.org/10.1088/1741-4326/ab023a	journal	June 2019
Avoidance of impurity-induced current quench using lower hybrid current drive Reinke, M. L.; Scott, S.; Granetz, R. Nuclear Fusion, Vol. 59, Issue 6 https://doi.org/10.1088/1741-4326/ab0eb2	journal	April 2019
Overview of new MAST physics in anticipation of first results from MAST Upgrade Harrison, J. R.; Akers, R. J.; Allan, S. Y. Nuclear Fusion, Vol. 59, Issue 11 https://doi.org/10.1088/1741-4326/ab121c	journal	June 2019
Progress in disruption prevention for ITER Strait, E. J.; Barr, J. L.; Baruzzo, M. Nuclear Fusion, Vol. 59, Issue 11 https://doi.org/10.1088/1741-4326/ab15de	journal	June 2019
Machine learning for disruption warnings on Alcator C-Mod, DIII-D, and EAST Montes, K. J.; Rea, C.; Granetz, R. S. Nuclear Fusion, Vol. 59, Issue 9 https://doi.org/10.1088/1741-4326/ab1df4	journal	July 2019
Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV Kong, M.; Blanken, T. C.; Felici, F. Nuclear Fusion, Vol. 59, Issue 7 https://doi.org/10.1088/1741-4326/ab1e1e	journal	June 2019
A real-time machine learning-based disruption predictor in DIII-D Rea, C.; Montes, K. J.; Erickson, K. G. Nuclear Fusion, Vol. 59, Issue 9 https://doi.org/10.1088/1741-4326/ab28bf	journal	July 2019
A power-balance model of the density limit in fusion plasmas: application to the L-mode tokamak Zanca, P.; Sattin, F.; Escande, D. F. Nuclear Fusion, Vol. 59, Issue 12 https://doi.org/10.1088/1741-4326/ab3b31	journal	September 2019
Energy and particle confinement in JET H-mode plasma Maslov, M.; Boboc, A.; Brix, M. Nuclear Fusion, Vol. 60, Issue 3 https://doi.org/10.1088/1741-4326/ab6482	journal	January 2020
A semi-supervised machine learning detector for physics events in tokamak discharges Montes, K. J.; Rea, C.; Tinguely, R. A. Nuclear Fusion, Vol. 61, Issue 2 https://doi.org/10.1088/1741-4326/abcdb9	journal	January 2021
The upgraded ASDEX Upgrade contribution to the ITPA confinement database: description and analysis Ryter, F.; Angioni, C.; Tardini, G. Nuclear Fusion, Vol. 61, Issue 4 https://doi.org/10.1088/1741-4326/abe4b0	journal	March 2021
Real-time prediction of high-density EAST disruptions using random forest Hu, W. H.; Rea, C.; Yuan, Q. P. Nuclear Fusion, Vol. 61, Issue 6 https://doi.org/10.1088/1741-4326/abf74d	journal	May 2021
Overview of the TCV tokamak experimental programme Reimerdes, H.; Agostini, M.; Alessi, E. Nuclear Fusion, Vol. 62, Issue 4 https://doi.org/10.1088/1741-4326/ac369b	journal	March 2022
Enhanced particle transport events approaching the density limit of the J-TEXT tokamak Long, T.; Diamond, P. H.; Ke, R. Nuclear Fusion, Vol. 61, Issue 12 https://doi.org/10.1088/1741-4326/ac36f2	journal	November 2021
Model for access and stability of the X-point radiator and the threshold for marfes in tokamak plasmas Stroth, U.; Bernert, M.; Brida, D. Nuclear Fusion, Vol. 62, Issue 7 https://doi.org/10.1088/1741-4326/ac613a	journal	April 2022
Integrated deep learning framework for unstable event identification and disruption prediction of tokamak plasmas Zhu, J. X.; Rea, C.; Granetz, R. S. Nuclear Fusion, Vol. 63, Issue 4 https://doi.org/10.1088/1741-4326/acb803	journal	March 2023
IDP-PGFE: an interpretable disruption predictor based on physics-guided feature extraction Shen, C.; Zheng, W.; Ding, Y. Nuclear Fusion, Vol. 63, Issue 4 https://doi.org/10.1088/1741-4326/acbe0f	journal	March 2023
Greenwald density limit and power balance in tokamaks Morozov, D. Kh Journal of Physics: Conference Series, Vol. 941 https://doi.org/10.1088/1742-6596/941/1/012009	journal	December 2017
Density limit disruption prediction using a long short-term memory network on EAST Zhang, Kai; Chen, Dalong; Guo, Bihao Plasma Science and Technology, Vol. 22, Issue 11 https://doi.org/10.1088/2058-6272/abb28f	journal	September 2020
Origin of Tokamak Density Limit Scalings Gates, D. A.; Delgado-Aparicio, L. Physical Review Letters, Vol. 108, Issue 16 https://doi.org/10.1103/PhysRevLett.108.165004	journal	April 2012
First-Principles Density Limit Scaling in Tokamaks Based on Edge Turbulent Transport and Implications for ITER Giacomin, M.; Pau, A.; Ricci, P. Physical Review Letters, Vol. 128, Issue 18 https://doi.org/10.1103/PhysRevLett.128.185003	journal	May 2022
Integrated Real-Time Supervisory Management for Off-Normal-Event Handling and Feedback Control of Tokamak Plasmas Vu, Trang; Felici, Federico; Galperti, Cristian IEEE Transactions on Nuclear Science, Vol. 68, Issue 8 https://doi.org/10.1109/TNS.2021.3084410	journal	August 2021
Impurity radiation from a tokamak plasma Morozov, D. Kh.; Baronova, E. O.; Senichenkov, I. Yu. Plasma Physics Reports, Vol. 33, Issue 11 https://doi.org/10.1134/S1063780X07110037	journal	November 2007
A Survey of Thermal Instabilities in Tokamak Plasmas: Theory, Comparison with Experiment, and Predictions for Future Devices Stacey, W. M. Fusion Science and Technology, Vol. 52, Issue 1 https://doi.org/10.13182/FST07-A1485	journal	July 2007

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