A new analysis technique for Balmer line spectroscopy that enables recombination rate (particle sink) and ionization rate (particle source) inference in a closed divertor configuration is reported. Bayesian inference is employed to systematically utilize all available information from multiple Balmer lines and constrain parameter ranges by using prior knowledge about plasmas. While a closed-divertor facilitates detachment, neutral plugging typically leads to large spatial variations in plasma parameters. A forward model is developed to take into account non-uniformity in the plasma parameters and applied to test data generated by divertor plasma simulations. It is shown that the forward model robustly provides particle source and sink inference over a wide parameter range. In addition, the precision improves as more Balmer lines are resolved simultaneously. The new analysis technique is also applied to an L-mode ASDEX Upgrade plasma in the high-recycling regime. The inferred quantities and their profiles are consistent with the expectations of a high-recycling divertor plasma. The further insight into the detachment physics will be provided by using this new analysis technique.

Nishizawa, T., Cavedon, M., Reimold, F., Dux, R., Brida, D., Wu, H. (2020). Bayesian inference of particle source and sink in a closed-divertor using Balmer line spectroscopy. PLASMA PHYSICS AND CONTROLLED FUSION, 62(8) [10.1088/1361-6587/ab9732].

Bayesian inference of particle source and sink in a closed-divertor using Balmer line spectroscopy

Cavedon M.;
2020

Abstract

A new analysis technique for Balmer line spectroscopy that enables recombination rate (particle sink) and ionization rate (particle source) inference in a closed divertor configuration is reported. Bayesian inference is employed to systematically utilize all available information from multiple Balmer lines and constrain parameter ranges by using prior knowledge about plasmas. While a closed-divertor facilitates detachment, neutral plugging typically leads to large spatial variations in plasma parameters. A forward model is developed to take into account non-uniformity in the plasma parameters and applied to test data generated by divertor plasma simulations. It is shown that the forward model robustly provides particle source and sink inference over a wide parameter range. In addition, the precision improves as more Balmer lines are resolved simultaneously. The new analysis technique is also applied to an L-mode ASDEX Upgrade plasma in the high-recycling regime. The inferred quantities and their profiles are consistent with the expectations of a high-recycling divertor plasma. The further insight into the detachment physics will be provided by using this new analysis technique.
Articolo in rivista - Articolo scientifico
Bayesian inference; detachment; spectroscopy;
English
Nishizawa, T., Cavedon, M., Reimold, F., Dux, R., Brida, D., Wu, H. (2020). Bayesian inference of particle source and sink in a closed-divertor using Balmer line spectroscopy. PLASMA PHYSICS AND CONTROLLED FUSION, 62(8) [10.1088/1361-6587/ab9732].
Nishizawa, T; Cavedon, M; Reimold, F; Dux, R; Brida, D; Wu, H
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/354856
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