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Time-resonant tokamak plasma edge instabilities?

Author
Abstract

For a two week period during the Joint European Torus 2012 experimental campaign, the same high confinement plasma was repeated 151 times. The dataset was analysed to produce a probability density function (pdf) for the waiting times between edge-localized plasma instabilities (ELMs). The result was entirely unexpected. Instead of a smooth single peaked pdf, a succession of 4-5 sharp maxima and minima uniformly separated by 7-8 ms intervals was found. Here we explore the causes of this newly observed phenomenon, and conclude that it is either due to a naturally occurring self-organized plasma phenomenon or an interaction between the plasma and a real-time control system. If the maxima are a result of 'resonant' frequencies at which ELMs can be triggered more easily, then future ELM control techniques can, and probably will, use them. Either way, these results demand a deeper understanding of the ELM process.

Year of Publication
2014
Journal
Plasma Physics and Controlled Fusion
Volume
56
Number
7
Issue
7
Number of Pages
075017
Date Published
Jul
ISBN Number
0741-3335
URL
http://www.euro-fusionscipub.org/wp-content/uploads/2014/11/EFDP13058.pdf
DOI
10.1088/0741-3335/56/7/075017
PId
63d8b3401376cbc0bda7a01df91ddc7b
Alternate Journal
Plasma Phys. Control. Fusion
Label
OA
Journal Article
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