Identifying low-dimensional dynamics in type-I edge-localised-mode processes in JET plasmas

Edge localised mode (ELM) measurements from reproducibly similar plasmas in the Joint European Torus (JET) tokamak, which differ only in their gas puffing rate, are analysed in terms of the pattern in the sequence of inter-ELM time intervals. It is found that the category of ELM defined empirically...

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Veröffentlicht in:Physics of plasmas 2013-04, Vol.20 (4)
Hauptverfasser: Calderon, F. A., Dendy, R. O., Chapman, S. C., Webster, A. J., Alper, B., Nicol, R. M.
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Sprache:eng
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Zusammenfassung:Edge localised mode (ELM) measurements from reproducibly similar plasmas in the Joint European Torus (JET) tokamak, which differ only in their gas puffing rate, are analysed in terms of the pattern in the sequence of inter-ELM time intervals. It is found that the category of ELM defined empirically as type I—typically more regular, less frequent, and having larger amplitude than other ELM types—embraces substantially different ELMing processes. By quantifying the structure in the sequence of inter-ELM time intervals using delay time plots, we reveal transitions between distinct phase space dynamics, implying transitions between distinct underlying physical processes. The control parameter for these transitions between these different ELMing processes is the gas puffing rate.
ISSN:1070-664X
1089-7674
DOI:10.1063/1.4802793