Bremen 2017 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 6: Helmholtz Graduate School I
P 6.15: Poster
Montag, 13. März 2017, 16:30–18:30, HS Foyer
Bayesian inference of electron temperature and density from JET high resolution Thomson scattering and interferometer data — •Sehyun Kwak1,2, Jakob Svensson2, Sergey Bozhenkov2, Joanne Flanagan3, Mark Kempenaars3, Young-chul Ghim1, and JET Contributors3 — 1Dept. of Nuclear and Quantum Engineering, KAIST, Daejeon, South Korea — 2Max-Planck-Institut für Plasmaphysik, Greifswald, Germany — 3Culham Centre for Fusion Energy, Abingdon, UK
A Bayesian model for inferring electron temperature and density profiles from a combination of the high resolution Thomson scattering (HRTS) and interferometer systems at JET has been developed. The HRTS system measures spectra of Thomson scattered light, which depends on the local temperature and density. The interferometer measures line integrated density along a number of lines of sight. As the spatial channels and lines of sight of the HRTS and interferometer systems are differently located the temperature and density profiles need to be mapped to normalised flux coordinates (here using the EFIT code) so that the forward model predicts both HRTS and interferometer data simultaneously given the profiles. The prior temperature and density profiles are modelled as Gaussian processes with spatially varying smoothness properties (determined by hyperparameters). The posterior distribution of the temperature and density profile as well as their hyperparameters is explored by a Markov chain Monte Carlo (MCMC) scheme. Since the model includes both HRTS and interferometer systems, the HRTS calibration is done automatically.