Walkden, N. R., Wynn, A., Militello, F. et al. (5 more authors) (2017) Statistical analysis of the ion flux to the JET outer wall. Nuclear Fusion. 036016. ISSN 1741-4326
Abstract
Statistical analysis of the ion flux to the JET outer-wall is conducted in outer-wall limiter mounted Langmuir probe (OLP) time-series across a wide range of plasma current and line-averaged density during Ohmically heated horizontal target L-mode plasmas. The mean, μ, and the standard deviation, σ, of the ion-saturation current measured by the OLP show systematic variation with plasma current and density. Both increase as either plasma current decreases and/or density increases. Upon renormalization, achieved by subtraction of μ and rescaling by σ, the probability distribution functions (PDFs) of each signal collapse approximately onto a single curve. The shape of the curve deviates from a Γ distribution in the tail of the PDF and is better described by a log-normal distribution. The invariance in the shape of the PDF, which occurs over approximately four decades of the ordinate, is shown to be the result of a balance between the duration time of the average burst wave-form, τd and the waiting time between bursts, τw. This implies that the intermittency parameter, τd/τw , can be considered constant at the JET outer wall during horizontal target Ohmic L-mode operation. This result may be important both for model validation and prediction.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 Culham Centre for Fusion Energy. This is an author-produced version of a paper accepted for publication. Uploaded with permission of the publisher/copyright holder. Further copying may not be permitted; contact the publisher for details |
Keywords: | Langmuir probe,Ohmically heated,plasma wall flux |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 07 Jun 2017 09:45 |
Last Modified: | 06 Jan 2025 00:10 |
Published Version: | https://doi.org/10.1088/1741-4326/aa515a |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1088/1741-4326/aa515a |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:117449 |