Static and dynamic behaviour of plasma detachment in the divertor simulator experiment NAGDIS-II

N. Ohno, D. Nishijima, S. Takamura, Y. Uesugi, M. Motoyama, N. Hattori, H. Arakawa, N. Ezumi, S. Krasheninnikov, A. Pigarov, U. Wenzel

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166 Citations (Scopus)

Abstract

A comprehensive investigation has been performed of the static and dynamic behaviour of detached recombining plasmas in the linear divertor plasma simulator NAGDIS-II. For stationary plasma detachment, the transition from electron ion recombination (EIR) to molecular activated recombination (MAR) has been observed by injecting hydrogen gas into high density helium plasmas. The particle loss rate due to MAR is found to be comparable to that of EIR. Experiments have also been performed by the injection of a plasma heat pulse produced by RF heating into the detached helium plasma to demonstrate the dynamic behaviour of volumetric plasma recombination. Negative spikes in the Balmer series line emission were observed and found to be similar to the so called negative ELM observed in tokamak divertors. Observed Balmer spectra were analysed in detail using the collisional-radiative model. A rapid increase of the ion flux to the target plate was observed associated with the re-ionization of the highly excited atoms generated by EIR.

Original languageEnglish
Pages (from-to)1055-1065
Number of pages11
JournalNuclear Fusion
Volume41
Issue number8
DOIs
Publication statusPublished - Aug 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

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