학술논문

Bayesian inference of particle source and sink in a closed-divertor using Balmer line spectroscopy.
Document Type
Article
Source
Plasma Physics & Controlled Fusion. Aug2020, Vol. 62 Issue 8, p1-14. 14p.
Subject
*SPECTROMETRY
*PARTICLES
*SPATIAL variation
*PRIOR learning
Language
ISSN
0741-3335
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. [ABSTRACT FROM AUTHOR]