Articolo in rivista, 2021, ENG, 10.1088/1741-4326/abe3c7

Onset of tearing modes in plasma termination on JET: The role of temperature hollowing and edge cooling

Pucella G.; Buratti P.; Giovannozzi E.; Alessi E.; Auriemma F.; Brunetti D.; Ferreira D.R.; Baruzzo M.; Frigione D.; Garzotti L.; Joffrin E.; Lerche E.; Lomas P.J.; Nowak S.; Piron L.; Rimini F.; Sozzi C.; Van Eester D.

ENEA, Fusion and Nuclear Safety Department, C.R. Frascati, Italy; ISTP, Consiglio Nazionale Delle Ricerche, Milano, Italy; Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Padova, Italy; Culham Centre for Fusion Energy, Abingdon, Culham Centre for Fusion Energy, Abingdon, United Kingdom of Great Britain and Northern Ireland, United Kingdom; IPFN/IST, University of Lisbon, Lisbon, IPFN/IST, University of Lisbon, Portugal; Università Degli Studi di Roma Tor Vergata, Roma, Italy; CEA, IRFM, Saint-Paul-lez-Durance, France; Laboratory for Plasma Physics, Ecole Royale Militaire, Brussels, Belgium; Università Degli Studi di Padova, Padova, Italy.

In this work the onset of tearing modes in the termination phase of plasma pulses on JET is investigated. It is shown that the broadening or the shrinking of the current density profile, as a consequence of a core hollowing or an edge cooling of the electron temperature profile, strongly increases the probability of destabilizing a 2/1 tearing mode also in absence of an external trigger (e.g. a sawtooth crash). Two parameters are defined to highlight changes in the shape of the temperature profile that can lead to MHD instabilities and an empirical stability diagram is introduced into the space of the two new parameters. A large data-set of pulses carried out in the high-current scenario at JET with ITER-like wall is analyzed and criteria for the development of disruption alerts based on the two risk indicators for MHD instabilities are discussed, taking into account the different dynamics of the observed phenomena leading to the onset of 2/1 tearing modes.

Nuclear fusion (Online) 61 (4), pp. 046020-1–046020-12

Keywords

tearing modes, plasma termination, JET, temperature hollowing, edge cooling, onset

CNR authors

Sozzi Carlo, Nowak Silvana, Alessi Edoardo, Auriemma Fulvio

CNR institutes

ISTP – Istituto per la Scienza e Tecnologia dei Plasmi

ID: 453420

Year: 2021

Type: Articolo in rivista

Creation: 2021-04-29 15:47:59.000

Last update: 2024-01-09 07:27:04.000

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:453420

DOI: 10.1088/1741-4326/abe3c7

Scopus: 2-s2.0-85103180277

ISI Web of Science (WOS): 000629138100001