In metallic machines ICRH heating is playing an increasingly important role. One of its most recent applications on the Joint Europena Torus (JET) is sawtooth control by ICRH modulation, for avoiding triggering dangerous neo-classical tearing modes (NTMs) and counteracting impurity accumulation. Some of the main difficulties of these experiments are the assessment of the synchronization efficiency and the understanding of the main physical mechanisms at play. In this paper, three independent classes of statistical indicators are introduced to address these issues: Recurrence Plots, Convergent Cross Mapping and Transfer Entropy. The application to JET experiments with the ILW shows that the proposed indicators agree quite well among themselves and provide sound estimates of the efficiency of the synchronisation scheme investigated. They also support, with a shot to shot basis analysis and an estimate of the uncertainties, the interpretation that the fast ions play a fundamental role in the stabilization of the sawteeth, in both L and H mode. Proposals for experiments to be carried out in the future to consolidate the interpretation of the results are discussed.

Murari, A., Craciunescu, T., Peluso, E., Lerche, E., Gelfusa, M. (2017). On efficiency and interpretation of sawteeth pacing with on-axis ICRH modulation in JET. NUCLEAR FUSION, 57(12), 126057 [10.1088/1741-4326/aa87e7].

On efficiency and interpretation of sawteeth pacing with on-axis ICRH modulation in JET

Peluso E.;Gelfusa M.
2017

Abstract

In metallic machines ICRH heating is playing an increasingly important role. One of its most recent applications on the Joint Europena Torus (JET) is sawtooth control by ICRH modulation, for avoiding triggering dangerous neo-classical tearing modes (NTMs) and counteracting impurity accumulation. Some of the main difficulties of these experiments are the assessment of the synchronization efficiency and the understanding of the main physical mechanisms at play. In this paper, three independent classes of statistical indicators are introduced to address these issues: Recurrence Plots, Convergent Cross Mapping and Transfer Entropy. The application to JET experiments with the ILW shows that the proposed indicators agree quite well among themselves and provide sound estimates of the efficiency of the synchronisation scheme investigated. They also support, with a shot to shot basis analysis and an estimate of the uncertainties, the interpretation that the fast ions play a fundamental role in the stabilization of the sawteeth, in both L and H mode. Proposals for experiments to be carried out in the future to consolidate the interpretation of the results are discussed.
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore ING-IND/18 - Fisica dei Reattori Nucleari
English
sawteeth pacing; ICRH modulation; transfer entropy; recurrence plots; convergent cross mapping
Murari, A., Craciunescu, T., Peluso, E., Lerche, E., Gelfusa, M. (2017). On efficiency and interpretation of sawteeth pacing with on-axis ICRH modulation in JET. NUCLEAR FUSION, 57(12), 126057 [10.1088/1741-4326/aa87e7].
Murari, A; Craciunescu, T; Peluso, E; Lerche, E; Gelfusa, M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/240247
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