The role of plasma-atom/molecule interaction on power, particle and momentum balance during detachment

The role of plasma-atom/molecule interaction on power, particle and momentum balance during detachment

The role of plasma-atom/molecule interaction on power, particle and momentum balance during detachment 150 150 Mathew
UKAEA-CCFE-CP(21)06

The role of plasma-atom/molecule interaction on power, particle and momentum balance during detachment

In this work we provide experimental insights into the impact of plasma-molecule interactions on divertor detachment by applying new spectroscopic analysis techniques to the hydrogen Balmer line series to investigate how both atom and plasma-molecule interactions impact particle balance. Our analysis on a representative L-mode TCV density ramp discharge indicates that Molecular Activated Recombination ion sinks from H+2 and/or H are significantly (a factor ∼ 5) larger than Electron-Ion Recombination for TCV and are a significant contributor to the observed reduction in the outer divertor ion target flux. Such MAR reactions lead to the formation of excited atoms which contribute significantly to the measured hydrogenic line emission spectra and thus hydrogenic radiation. Such contributions should be accounted for when analysing the hydrogenic line series for inferring ionisation rates.

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Conference:
24th International Conference on Plasma Surface Interactions in Controlled Fusion Devices (PSI), South Korea, 24 - 29 January 2021
Published date:
16/02/2021
The published version of this paper is currently under embargo and will be available on 16/02/2023