Abstract
In particular circumstances, nonlinear systems can collapse suddenly and abruptly. Anomalous detection is therefore an important task. Unfortunately, many phenomena occurring in complex systems out of equilibrium, such as disruptions in tokamak thermonuclear plasmas, cannot be modelled from first principles in real-time compatible form and therefore data-driven, machine learning techniques are often deployed. A typical issue, for training these tools, is the choice of the most adequate examples. Determining the intervals, in which the anomalous behaviours manifest themselves, is consequently a challenging but essential objective. In this paper, a series of methods are deployed to determine when the plasma dynamics of the tokamak configuration varies, indicating the onset of drifts towards a form of collapse called disruption. The techniques rely on changes in various quantities derived from the time series of the main signals: from the embedding dimensions to the properties of recurrence plots and to indicators of transition to chaotic dynamics. The methods, being mathematically completely independent, provide quite robust indications about the intervals, in which the various signals manifest a pre-disruptive behaviour. Consequently, the signal samples, to be used for supervised machine learning predictors, can be defined precisely, on the basis of the plasma dynamics. This information can improve significantly not only the performance of machine learning classifiers but also the physical understanding of the phenomenon.
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References
Hadlock, C.R.: Six Sources of Collapse. Mathematical Association of America, Washington (2012).. (ISBN-10: 0883855798)
Chen, F.F.: An Indispensable Truth: How Fusion Power Can Save the Planet. Springer (2011).. (ISBN: 978-1-4419-7820-2)
Wesson, J., Campbell, D.J.: Tokamaks, Oxford University Press, 4th edn. ISBN: 0198509227 9780198509226.
Murari, A., Lungaroni, M., Gelfusa, M., Peluso, E., Vega, J.: Adaptive learning for disruption prediction in non-stationary conditions. Nucl. Fusion 59(8), 086037 (2019)
Murari, A., Rossi, R., Peluso, E., Lungaroni, M., Gaudio, P., Gelfusa, M., Ratta, G., Vega, J.: On the transfer of adaptive predictors between different devices for both mitigation and prevention of disruptions. Nucl. Fusion 60(5), 056003 (2020)
Murari, A., Rossi, R., Lungaroni, M., Baruzzo, M., Gelfusa, M.: Stacking of predictors for the automatic classification of disruption types to optimize the control logic. Nucl. Fusion 61(3), 036027 (2021)
Vega, J., Dormido-Canto, S., López, J.M., Murari, A., Ramírez, J.M., Moreno, R., Ruiz, M., Alvez, D., Felton, R.: Results of the JET real-time disruption predictor in the ITER-like wall campaigns. Fusion Eng. Des. 88(6–8), 1228–1231 (2013)
Vega, J., Murari, A., Dormido-Canto, S., Rattá, G.A., Gelfusa, M.: Disruption prediction with artificial intelligence techniques in tokamak plasmas. Nat. Phys. 18, 741–750 (2022)
Bagniewski, W., Ghil, M., Rousseau, D.D.: Automatic detection of abrupt transitions in paleoclimate records. Chaos 31, 13129 (2021)
Carpenter, S.R., Brock, W.A.: Rising variance: a leading indicator of ecological transition. Ecol. Lett. 9, 311–318 (2006)
Goswami, B., Boers, N., Rheinwalt, A., Marwan, N., Heitzig, J., Breitenbach, S.F.M., Kurths, J.: Abrupt transitions in time series with uncertainties. Nat. Commun. 6, 48 (2018)
Schiepek, G., Schöller, H., de Felice, G., Steffensen, S.V.: Convergent validation of methods for the identification of psychotherapeutic phase transitions in time series of empirical and model systems. Front. Psychol. 11, 1970 (2020)
Scheffer, M., Carpenter, S.R., Lenton, T.M., Bascompte, J., Brock, W., Dakos, V., van de Koppel, J., van de Leemput, I.A., Levin, S.A., van Nes, E.H., Pascual, M., Vandermeer, J.: Anticipating critical transitions. Science 338, 344–348 (2012)
Scheffer, M., Bascompte, J., Brock, W.A., Brovkin, V., Carpenter, S.R., Dakos, V., Held, H., van Nes, E.H., Rietkerk, M., Sugihara, G.: Early-warning signals for critical transitions. Nature 461, 53–59 (2009)
Neuman, Y., Marwan, N., Cohen, Y.: Change in the embedding dimension as an indicator of an approaching transition. PLoS ONE 9(6), e101014 (2014)
Kéfi, S., Dakos, V., Scheffer, M., van Nes, E.H., Rietkerk, M.: Early warning signals also precede non-catastrophic transitions. Oikos 122, 641–648 (2013)
Takens, F.: Dettecting strage attractors in turbulence, In: Rand D., Young L.S. (eds) Dynamical Systems and Turbulence. Warwick 1980. Lecture Notes in Mathematics, vol. 898. Springer, Berlin
Kantz, H., Schreiber, T.: Nonlinear Time Series Analysis. University Press, Cambridge (1997)
Kennel, M., Brown, R., Abarbanel, H.: Determining embedding dimension for phase-space reconstruction using a geometrical construction. Phys. Rev. A 45(6), 3403–3411 (1992)
Poincare, H.: Sur le problème des trois corps et les équations de la dynamique. Acta Math. 13(1), A3–A270 (1980)
Eckmann, J.-P., Kamphorst, S.O., Ruelle, D.: Recurrence plots of dynamical systems. Europhys. Lett. 4, 973–977 (1987)
Marwan, N., Romano, M.C., Thiel, M., Kurths, J.: Recurrence plots for the analysis of complex systems. Phys. Rep. 438(5–6), 237–329 (2007)
Goswami, B.: A brief introduction to nonlinear time series analysis and recurrence plots. Vibration 2(4), 332–368 (2019)
Mindlin, G.M., Gilmore, R.: Topological analysis and synthesis of chaotic time series. Phys. D 58(1–4), 229–242 (1992)
Koebbe, M., Mayer-Kress, G.: Use of recurrence plots in the analysis of time-series data. In: Casdagli M., Eubank S. (eds.) Proceedings of SFI Studies in the Science of Complexity, vol. XXI, pp. 361–378. Addison-Wesley, Reading, Redwood City (1992)
Eroglu, D., Marwan, N., Prasad, S., Kurths, J.: Finding recurrence networks’ threshold adaptively for a specific time series. Nonlinear Process. Geophys. 21, 1085 (2014)
Schinkel, S., Dimigen, O., Marwan, N.: Selection of recurrence threshold for signal detection. Eur. Phys. J. Spec. Top. 164, 45–53 (2008)
Zbilut, J.P., Koebbe, M., Loeb, H., Mayer-Kress, G.: Use of recurrence plots in the analysis of heart beat intervals. In: Proceedings of the IEEE Conference on Computers in Cardiology, Chicago, pp. 263–266. IEEE Computer Society Press (1990)
Marwan, N., Wessel, N., Meyerfeldt, U., Schirdewan, A., Kurths, J.: Recurrence plot based measures of complexity and its application to heart rate variability data. Phys. Rev. E 66, 026702 (2002)
Meyers, A., Buqammaz, M., Yang, H.: Cross-recurrence analysis for pattern matching of multidimensional physiological signals. Chaos 30, 123125 (2020)
Lacasa, L., Luque, B., Luque, J., Nuño, J.C.: The visibility graph: a new method for estimating the Hurst exponent of fractional Brownian motion. EPL 86, 30001 (2009)
Luque, B., Lacasa, L., Ballesteros, F., Luque, J.: Horizontal visibility graphs: exact results for random time series. Phys. Rev. E 80, 046103 (2009)
Xu, X., Zhang, J., Small, M.: Superfamily phenomena and motifs of networks induced from time series. PNAS 105, 19601 (2008)
Marwan, N., Donges, J.F., Zou, Y., Donner, R.V., Kurths, J.: Complex network approach for recurrence analysis of time series. Phys. Lett. A 373, 4246 (2009)
Donner, R.V., Small, M., Donges, J.F., Marwan, N., Zou, Y., Xiang, R., Kurths, J.: Recurrence-based time series analysis by means of complex network methods. Int. J. Bifurc. Chaos 21, 1019 (2011)
Eroglu, D., Marwan, N., Stebich, M., Kurths, J.: Multiplex recurrence networks. Phys. Rev. E 97, 012312 (2018)
Lacasa, L., Nicosia, V., Latora, V.: Network structure of multivariate time series. Sci. Rep. 5, 15508 (2015)
Ngamga, E.J., Senthilkumar, D.V., Prasad, A., Parmananda, P., Marwan, N., Kurths, J.: Distinguishing dynamics using recurrence-time statistics. Phys. Rev. E 85, 026217 (2012)
Ngamga, E.J., Nandi, A., Ramaswamy, R., Romano, M.C., Thiel, M., Kurths, J.: Recurrence analysis of strange nonchaotic dynamics. Phys. Rev. E 75, 036222 (2007)
Gao, J.B.: Recurrence time statistics for chaotic systems and their applications. Phys. Rev. Lett. 83, 3178 (1999)
Ngamga, E.J., Buscarino, A., Frasca, M., Fortuna, L., Prasad, A., Kurths, J.: Recurrence analysis of strange nonchaotic dynamics in driven excitable systems. Chaos 18, 013128 (2008)
Little, M., McSharry, P., Roberts, S., Costello, D., Moroz, I.: Exploiting nonlinear recurrence and fractal scaling properties for voice disorder detection. Biomed. Eng. Online 6, 23 (2007)
Gottwald, G.A., Melbourne, I.: A new test for chaos in deterministic systems. Proc. R. Soc. A 460, 603–611 (2004)
Gottwald, G.A., Melbourne, I.: Testing for chaos in deterministic systems with noise. Phys. D 212(1–2), 100–110 (2005)
Gottwald, G.A., Melbourne, I.: Comment on “Reliability of the 0–1 test for chaos. Phys. Rev. E 77, 028201 (2008)
Dawes, J.H.P., Freeland, M.C.: The ‘0–1 test for chaos’ and strange nonchaotic attractors. https://people.bath.ac.uk/jhpd20/publications/sna.pdf (2008)
Toker, D., Sommer, F.T., D’Esposito, M.: A simple method for detecting chaos in nature. Commun. Biol. 3, 11 (2020)
Koutsoyiannis, D.: Time’s arrow in stochastic characterization and simulation of atmospheric and hydrological processes. Hydrol. Sci. J. 64–9, 1013–1037 (2019)
Cox, D.R.: Statistical analysis of time series: some recent developments. Scan. J. Stat. 8, 93–115 (1981)
Lombardo, F., Volpi, E., Koutsoyannis, D., Paplexiou, A.M.: Just two moments! A cautionary note against use of high-order moments in multifractal models in hydrology. Hydrol. Earth Syst. Sci. 18, 243–255 (2014)
Sackellares, J., Iasemidis, L., Shiau, D., Gilmore, R., Roper, S.: Epilepsy when chaos fails. In: Lehnertz, K., Arnhold, J., Grassberger, P., Elger, C.E. (eds.) Chaos in the Brain?, pp. 112–133. World Scientific, Singapore (2000)
Datseris, G.: DynamicalSystems.jl: a Julia software library for chaos and nonlinear dynamics. J. Open Source Softw. 3(23), 598 (2018)
Acknowledgements
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom Research and Training Programme 2014–2018 and 2019–2020 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200-EUROfusion). Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.
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*See the author list of ‘Overview of JET results for optimising ITER operation’ by J.Mailloux et al. l 2022 Nucl. Fusion 62 042026.
Appendices
Appendix 1: Database
This appendix provides some details (see Table
1) about the characteristics of the discharges analysed in the paper. The choice of the individual discharges has been motivated by the intention to cover a wider range of experimental conditions.
Appendix 2: Embedding dimension
See Table
2.
Appendix 3: 0–1 chaos test results
See Tables
3 and
4.
Appendix 4: Results for the indicators evaluating the similarity between recurrence plots
See Tables
5 and
6.
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Craciunescu, T., Murari, A. & JET Contributors*. Detection of changes in the dynamics of thermonuclear plasmas to improve the prediction of disruptions. Nonlinear Dyn 111, 3509–3523 (2023). https://doi.org/10.1007/s11071-022-08009-x
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DOI: https://doi.org/10.1007/s11071-022-08009-x