The role of hydrogen molecular effects on detachment in Magnum-PSI

G.R.A. Akkermans; I. G.J. Classen; R. Perillo; H. J. Van Der Meiden; F. Federici; S. Brezinsek

doi:10.1063/5.0017714

The role of hydrogen molecular effects on detachment in Magnum-PSI

G.R.A. Akkermans (Corresponding author), I. G.J. Classen, R. Perillo, H. J. Van Der Meiden, F. Federici, S. Brezinsek

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21 Citations (Scopus)

Abstract

The hydrogen plasma-chemical processes responsible for tokamak divertor detachment are studied experimentally in the linear device Magnum-PSI, with a focus on molecular activated recombination (MAR) in hydrogen plasmas. Hydrogen plasmas with electron densities up to 6 × 10 20 m - 3 were created in Magnum-PSI, and hydrogen gas puffing was used to locally enhance plasma-neutral interaction. Thomson scattering and Balmer line spectroscopy measurements show that as neutral pressure is increased, the plasma passes through regimes dominated by ionization, MAR, and electron-ion recombination in turn. Heat and particle fluxes decrease monotonically with pressure. Fulcher band measurements show that in our plasma conditions, a simple model based on Franck-Condon excitation of a thermal vibrational distribution fails to describe the vibrational distribution of the upper state. These results serve as a benchmark for modeling suites that aim to simulate the ITER divertor and motivates their accurate treatment of the discussed processes, particularly MAR.

Original language	English
Article number	102509
Number of pages	12
Journal	Physics of Plasmas
Volume	27
Issue number	10
DOIs	https://doi.org/10.1063/5.0017714
Publication status	Published - 1 Oct 2020

Funding

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under Grant Agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. We acknowledge the support of the Magnum-PSI Facility Team at DIFFER. The Magnum-PSI facility at DIFFER has been funded by the Netherlands Organization for Scientific Research (NWO) and EURATOM.

Funders	Funder number
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
European Union's Horizon 2020 - Research and Innovation Framework Programme	633053
European Union's Horizon 2020 - Research and Innovation Framework Programme
Nederlandse Organisatie voor Wetenschappelijk Onderzoek

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10.1063/5.0017714

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AU - Federici, F.

AU - Brezinsek, S.

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The role of hydrogen molecular effects on detachment in Magnum-PSI

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