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22-27 October 2018
Mahatma Mandir Conference Centre
Asia/Kolkata timezone
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Early identification of disruption paths for prevention and avoidance

23 Oct 2018, 08:30
4h
Mahatma Mandir Conference Centre

Mahatma Mandir Conference Centre

Gandhinagar (nearest Airport: Ahmedabad), India
Poster P1 Posters

Speaker

Dr Carlo Sozzi (Istituto di Fisica del Plasma - CNR, Milano, Italy)

Description

Disruption prevention in the perspective of high performance, high current, long duration plasma discharges requires a substantial evolution of the schemes applied in most of the present tokamaks. An efficient prevention scheme requires the early identification of the nature of the off-normal behavior possibly leading to a disruption and the automatic selection of the appropriated countermeasure, either avoidance or mitigation. The development of such comprehensive scheme is being pursued in a coordinate effort. For the purpose of the avoidance, on which this paper is focused, the disruption can be seen as the result of the interplay of the physical events and of the control system responses to them and to the technical failures. The building blocks of such description should include the integration of several sets of plasma scalar data, plasma profile data, magneto-hydrodynamics indicators and engineering data. Previous work has shown the potential of the Generative Topographic Mapping (GTM) [Bishop C., Neural Comp. 10, 1998] algorithm for identification and discrimination of the disruptive operational space in tokamak devices [Pau A.,Ph.D Thesis, paduaresearch.cab.unipd.it/6664/, 2014; Cannas B., PPCF56, 2014] . In this paper it is shown that the magnetic fluctuations associated with rotating MHD modes can be characterized using a set of observables derived from the Singular Value Decomposition applied to the data collected by an array of pick-up coils. They can provide an input to the GTM analysis such that a clustering separating disruptive and non-disruptive timeslices can be found. A further source of information comes from the analysis of the sequences of events recorded by the machine control system. The analysis of such sequences shows that disruptions and non-disruptive terminations generally follow different paths, i.e. are not populating equally the same sequences. Moreover, the time analysis of the most populated disruptions paths shows that in most of the cases the sequence can be recognized with an advance ranging about from 0.15s to 1.5s with respect to the disruption time. Such information is readily available to the control system and can contribute to the early triggering of the avoidance action. Details of such combined analysis and application to different databases of JET, TCV and AUG tokamaks will be discussed in the paper.
Country or International Organization Italy
Paper Number EX/P1-22

Primary author

Dr Carlo Sozzi (Istituto di Fisica del Plasma - CNR, Milano, Italy)

Co-authors

Prof. Alessandra Fanni (Dip. Ing. Elettrica e Elettronica, Univ. of Cagliari, Cagliari, Italy) Dr Alessandro Pau (Dip. Ing. Elettrica e Elettronica, Univ. of Cagliari, Cagliari, Italy) Dr Andrea Murari (Consorzio RFX, Padova, Italy) Dr Anna Teplukhina (Swiss Plasma Centre - EPFL, Lausanne, Switzerland) Dr Barbara Cannas (Dip. Ing. Elettrica e Elettronica, Univ. of Cagliari, Cagliari, Italy) Dr Cesidio Cianfarani (ENEA C. R. Frascati, Dipartimento FSN, Frascati, Italy) Dr Cristian Galperti (Swiss Plasma Centre - EPFL, Lausanne, Switzerland) Dr Diogo Ferreira (Inst. de Plasmas e Fusao Nuclear, IST, Lisboa, Portugal) Dr Edoardo Alessi (Istituto di Fisica del Plasma - CNR, Milano, Italy) Dr Emmanuel Joffrin (CEA - IRFM, St Paul Les Durance, France) Dr Emmanuele Peluso (University of Rome “Tor Vergata'', Roma, Italy) Dr Ernesto Lerche (Laboratory for Plasma Physics, ERM/KMS, Brussels, Belgium) Dr Ewa Pawelec (Inst. of Physics, University of Opole, Opole, Poland) Dr Federico Felici (Swiss Plasma Centre - EPFL, Lausanne, Switzerland) Dr Fernanda Rimini (Culham Centre for Fusion Energy, Abingdon, United Kingdom) Dr Florian Koechl (Culham Centre for Fusion Energy, Abingdon, United Kingdom) Dr Gediminas Stakunas (Lithuanian Energy Institute, Kaunas, Lithuania) Dr Giuliana Sias (Dip. Ing. Elettrica e Elettronica, Univ. of Cagliari, Cagliari, Italy) Dr Giuseppe Rattà (Lab. Nacional de Fusión, CIEMAT, Madrid, Spain) Dr Irina Ivanova-Stanik (Inst. of Plasma Phys. and Laser Microfusion, Warsaw, Poland) Dr Irina Voitsekhovitch (Culham Centre for Fusion Energy, Abingdon, United Kingdom) Dr Jesus Vega (Lab. Nacional de Fusión, CIEMAT, Madrid, Spain) Dr Marc Maraschek (Max-Planck-Institut für Plasmaphysik, Garching, Germany) Dr Matteo Baruzzo (Consorzio RFX, Padova, Italy) Dr Matthias Bernert (Max-Planck-Institut für Plasmaphysik, Garching, Germany) Dr Michela Gelfusa (University of Rome “Tor Vergata'', Roma, Italy) Dr Michele Lungaroni (University of Rome “Tor Vergata'', Roma, Italy) Dr Olivier Sauter (Swiss Plasma Centre – EPFL, Lausanne, Switzerland) Dr Ondrej Kudlacek (Max-Planck-Institut für Plasmaphysik, Garching, Germany) Dr Paolo Sparapani (Dip. Ing. Elettrica e Elettronica, Univ. of Cagliari, Cagliari, Italy) Dr Peter Lomas (Culham Centre for Fusion Energy, Abingdon, United Kingdom) Dr Rita Delogu (Consorzio RFX, Padova, Italy) Dr Sara Carcangiu (Dip. Ing. Elettrica e Elettronica, Univ. of Cagliari, Cagliari, Italy) Dr Sergei Gerasimov (Culham Centre for Fusion Energy, Abingdon, United Kingdom) Dr Thomas Blanken (Eindhoven University of Technology, Eindhoven, Netherlands) Dr Tommaso Bolzonella (Consorzio RFX, Padova, Italy) Dr Umar Sheik (Swiss Plasma Centre – EPFL, Lausanne, Switzerland)

Presentation Materials

Paper