Profile Shape Parameterization of JET Electron Temperature and Density Profiles

The temperature and density profiles of the Joint European Torus are parameterized using log-additive models in the control variables. Predictive error criteria are used to determine which terms in the log-linear model to include. The density and temperature profiles are normalised to their line ave...

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Bibliographic Details
Published in:arXiv.org 2018-03
Main Authors: Schunke, Beatrix, Kaya Imre, Riedel, Kurt S
Format: Article
Language:English
Subjects:
Beam injection
Cyclotron resonance
Density
Electron energy
Heating
Joint European Torus
Mathematical models
Neutral beams
Parameterization
Predictive control
Safety factors
Temperature dependence
Temperature profiles
Temperature scales
Toruses
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Summary:The temperature and density profiles of the Joint European Torus are parameterized using log-additive models in the control variables. Predictive error criteria are used to determine which terms in the log-linear model to include. The density and temperature profiles are normalised to their line averages (\(\bar{n}\) and \(\bar{T}\)). The normalised Ohmic density shape depends primarily on the parameter \(\bar{n}/B_t\), where \(B_t\) is the toroidal magnetic field. Both the Low-mode (L-mode) and edge localized mode-free (ELM-free) high mode (H-mode) temperature profile shapes depend strongly on the type of heating power, with ion cyclotron resonant heating producing a more peaked profile than neutral beam injection. Given the heating type dependence, the L-mode temperature shape is nearly independent of the other control variables. The H-mode temperature shape broadens as the effective charge, \(Z_{eff}\), increases. The line average L-mode temperature scales as \(B_t^{.96}\)(Power per particle)\(^{.385}\). The L-mode normalized density shape depends primarily on the ratio of line average density, \(\bar{n}\), to the edge safety factor, \(q_{95}\). As \(\bar{n}/q_{95}\) increases, the profile shape broadens. The current, \(I_p\), is the most important control variable for the normalized H-mode density. As the current increases, the profile broadens and the gradient at the edge sharpens. Increasing the heating power, especially the ion cyclotron resonant heating, or decreasing the average density, peaks the H-mode density profile slightly.
ISSN:2331-8422
DOI:10.48550/arxiv.1803.10895