Time-Resonant Tokamak Plasma Edge Instabilities?
Abstract
For a two week period during the Joint European Torus (JET) 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-localised 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 millisecond intervals was found. Here we explore the causes of this newly observed phenomenon, and conclude that it is either due to a self-organised 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 ELMing process.
Cite
@article{arxiv.1310.0287,
title = {Time-Resonant Tokamak Plasma Edge Instabilities?},
author = {A. J. Webster and R. O. Dendy and F. A. Calderon and S. C. Chapman and E. Delabie and D. Dodt and R. Felton and T. N. Todd and F. Maviglia and J. Morris and V. Riccardo and B. Alper and S Brezinsek and P. Coad and J. Likonen and M. Rubel and JET EFDA Contributors},
journal= {arXiv preprint arXiv:1310.0287},
year = {2014}
}
Comments
10 pages, 4 figures