Probability distribution functions for ELM bursts in a series of JET tokamak discharges
UNSPECIFIED. (2003) Probability distribution functions for ELM bursts in a series of JET tokamak discharges. PLASMA PHYSICS AND CONTROLLED FUSION, 45 (5). pp. 747-758. ISSN 0741-3335Full text not available from this repository.
A novel statistical treatment of the full raw edge localized mode (ELM) signal from a series of previously studied JET plasmas is tested. The approach involves constructing probability distribution functions (PDFs) for ELM amplitudes and time separations, and quantifying the fit between the measured PDFs and model distributions (Gaussian, inverse exponential) and Poisson processes. Uncertainties inherent in the discreteness of the raw signal require the application of statistically rigorous techniques to distinguish ELM data points from background, and to extrapolate peak amplitudes. The accuracy of PDF construction is further constrained by the relatively small number of ELM bursts (several hundred) in each sample. In consequence the statistical technique is found to be difficult to apply to low frequency (typically Type 1) ELMs, so the focus is narrowed to four JET plasmas with high frequency (typically Type III) ELMs. The results suggest that there may be several fundamentally different kinds of Type III ELMing process at work. It is concluded that this novel statistical treatment can be made to work, may have wider applications to ELM data, and has immediate practical value as an additional quantitative discriminant between classes of ELMing behaviour.
|Item Type:||Journal Article|
|Subjects:||Q Science > QC Physics|
|Journal or Publication Title:||PLASMA PHYSICS AND CONTROLLED FUSION|
|Publisher:||IOP PUBLISHING LTD|
|Official Date:||May 2003|
|Number of Pages:||12|
|Page Range:||pp. 747-758|
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