A locked mode indicator for disruption prediction on JET and ASDEX upgrade

G. Sias , B. Cannas , A. Fanni , A. Murari (1) , A. Pau , Davide Galassi (2)

1 Consorzio RFX Associazione EURATOM ENEA per la Fusione
2 M2P2 - Laboratoire de Mécanique, Modélisation et Procédés Propres

The aim of this paper is to present a signal processing algorithm that, applied to the raw Locked Mode signal, allows us to obtain a disruption indicator in principle exploitable on different tokamaks. A common definition of such an indicator for different machines would facilitate the development of portable systems for disruption prediction, which is becoming of increasingly importance for the next tokamak generations. Moreover, the indicator allows us to overcome some intrinsic problems in the diagnostic system such as drift and offset. The behavior of the proposed indicator as disruption predictor, based on crossing optimized thresholds of the signal amplitude, has been analyzed using data of both JET and ASDEX Upgrade experiments. A thorough analysis of the disruption prediction performance shows how the indicator is able to recover some missed and tardy detections of the raw signal. Moreover, it intervenes and corrects premature or even wrong alarms due to, e.g., drifts and/or offsets.

Mots clés: Tokamak; Disruption prediction; Locked mode signal; Disruption indicators; Feature extraction

Domaines: Mécanique des fluides [physics.class-ph]; Milieux fluides et réactifs

G. Sias, B. Cannas, A. Fanni, A. Murari, A. Pau, et al.. A locked mode indicator for disruption prediction on JET and ASDEX upgrade. Fusion Engineering and Design, 2019, 138, pp.254-266. ⟨10.1016/j.fusengdes.2018.11.021⟩. ⟨hal-02177084⟩