X-ray observations of helium-like scandium from the alcator c-mod tokamak

J.E. Rice, M.A. Graf, J.L. Terry, E.S. Marmar, K. Giesing, F. Bombarda

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Scandium (Z = 21) has been injected into the Alcator C-Mod tokamak. X-ray wavelengths of An = 1 transitions to the ground state in Sc19+and Sc18+have been accurately determined. Time-resolved spectra have been obtained from different radial locations following the injections and have been compared with favourable agreement to the results of collisional radiative-transport code modelling. X-rays emitted from the outermost regions of the plasma (r/al≥) appear in time after x-ray emission from the plasma centre. These x-rays arise from upper levels in Scl5+ populated by radiative recombination of Sc20+, which can only exist in the outer regions after the scandium has penetrated to the plasma centre, become ionized to Sc20+, and diffused back out before recombining. The density of scandium in the plasma has been determined for a variety of operating conditions. Only about 10% of the injected scandium penetrates to the plasma centre, and the scandium density in the plasma decreases with increasing electron density. © 1995 IOP Publishing Ltd.
Original languageEnglish
Pages (from-to)893 - 905
Number of pages13
JournalJournal of Physics B: Atomic, Molecular and Optical Physics
Issue number5
Publication statusPublished - 14 Mar 1995
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

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