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

TitleThe role of hydrogen molecular effects on detachment in Magnum-PSI
Publication TypeJournal Article
Year of Publication2020
AuthorsG.RA Akkermans, I.GJ Classen, R. Perillo, H.J van der Meiden, G. Federici, S. Brezinsek
JournalPhysics of Plasmas
Volume27
Issue10
Pagination102509
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 6×1020 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.

DOI10.1063/5.0017714
Division

FP

Department

PEPD

PID

68b83dee80eac62f88e3c229c4b90e48

Alternate TitlePhys. Plasmas

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