ELMs and strike point movements

TitleELMs and strike point movements
Publication TypeJournal Article
Year of Publication2008
AuthorsE.R Solano, S. Jachmich, F. Villone, N. Hawkes, Y. Corre, B. Alper, A. Loarte, R.A. Pitts, K. Guenther, A. Korotkov, M. Stamp, P. Andrew, J. Conboy, T. Bolzonella, M. Kempenaars, A. Cenedese, E. Rachlew
JournalNuclear Fusion
Volume48
Number6
Pagination12
Date PublishedJun
Type of ArticleArticle
ISBN Number0029-5515
Accession NumberISI:000257324500006
Keywordsdivertor, EDGE LOCALIZED MODES, I ELMS, INSTABILITIES, JET, MAGNETOHYDRODYNAMIC STABILITY, MHD ACTIVITY, PLASMAS, TOKAMAKS, TRANSPORT BARRIER
Abstract

A detailed study of position changes of plasma strike points before and after edge localized modes (ELMs) in JET was carried out. A hypothesis being tested is that in an ELM previously closed edge field lines would open up, releasing plasma current and leading to the formation of a new, smaller separatrix. It was observed that after each ELM strike points have shifted a few centimetres towards the plasma centre ( up in JET). In some cases a transient ( 10 cm) jump of strike positions was observed first. It was followed by an equally fast jump down to the shifted strike positions. Such behaviour has not been described in previous computational models of the ELM. Therefore two novel instability mechanisms are presented, which contribute to explain the changes in strike point position: an X-point instability, due to positive toroidal current density at the X-point, and a diamagnetic instability, due to negative inboard toroidal current density.

URL<Go to ISI>://000257324500006
Division

Fusion Physics

PID

a045bb467bfbb13b21cb0685a51c5b3f

Alternate TitleNucl. Fusion

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