Identifying low-dimensional dynamics in type-I edge-localised-mode processes in JET plasmas
- Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom)
- EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)
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.
- OSTI ID:
- 22130439
- Journal Information:
- Physics of Plasmas, Vol. 20, Issue 4; Other Information: (c) 2013 EURATOM; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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