Spectroscopic measurements of light impurity peaking after pellet injection on TEXT

E. J. Synakowski, R. D. Bengtson, A. Ouroua, A. J. Wootton, S. K. Kim

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Light impurity density profiles following hydrogen gas puff and hydrogen pellet fuelling have been obtained via charge exchange recombination spectroscopy on TEXT. After hydrogen pellet fuelling, C+6 and O+8 profiles are more strongly peaked on axis than the electron density profile. In contrast, light impurity profiles measured during sawtoothing high density gas puff fuelled discharges peak to a lesser degree relative to the electrons, with lower central densities than in the pellet case. The shapes of the peaked pellet impurity profiles are well described by neoclassical theory. The measured transport coefficients are larger than neoclassical values. The inferred inward convective velocity is consistent with values measured by impurity injection during sawtoothing discharges, but the diffusion coefficient is an order of magnitude lower than that obtained with impurity injection.

Original languageEnglish
Pages (from-to)311-315
Number of pages5
JournalNuclear Fusion
Volume29
Issue number2
DOIs
StatePublished - Feb 1989

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