Advertisement

Edge nT/nD by Two-Photon Induced Ly-α Fluorescence

  • K. Grützmacher
  • M. I. de la Rosa
  • J. Seidel
  • A. Steiger
  • G. Fußmann
  • W. Bohmeyer
  • D. Voslamber

Abstract

Recent theoretical and experimental investigations had promising results concerning the potential of Doppler-free two-photon induced Lyman-α fluorescence (2γLy-α) as a means for selective direct measurements of atomic densities of hydrogen isotopes in magnetically confined fusion plasmas. Even under tokamak conditions, all the two-photon absorption profiles of H, D, and T exhibit sharp, nearly unshifted central components with typical widths fitting well with the bandwidth of pulsed single-mode laser spectrometers which will be able to deliver the required power and quality needed for tokamak diagnostics. A first 2γ Ly-α fluorescence signal was observed at the plasma generator PSI-1 of IPP Berlin with high spatial resolution (ø 3mm, 8 mm length) in a pure deuterium plasma beam, ø 100 mm, ne ≈ 5·1012 cm-3, Te ≈ 5 eV. We are therefore convinced, that measurements of the nT/nD ratio from 0.1 to 10 will be possible in the edge plasma of ITER, with single shot accuracy better than 20% and with high spatial and temporal resolution at a laser repetition rate of 50 Hz. The detection limit for each isotope is estimated to be 109 cm-3.

Keywords

Hydrogen Isotope Laser Repetition Rate ASDEX Upgrade Relativistic Doppler Effect Motional Stark Effect 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    . D. Voslamber, Determination of neutral particle density and magnetic field direction from laser-induced Lyman-a fluorescence, II – Two-photon excitation, Report EUR-CEA-FC-1387 1990.Google Scholar
  2. 2.
    . D. Voslamber, Some novel concepts for spectroscopic diagnostics in tokamaks, in: Spectral Line Shapes, Vol. 8(AIP Conf. Proc. 328), A.D. May, J.R. Drummond, E. Oks, eds., American Institute of Physics, New York 1995.Google Scholar
  3. 3.
    J. Seidel and D. Voslamber, to be publishedGoogle Scholar
  4. 4.
    H. Behrendt, W. Bohmeyer, L. Dietrich, G. Fussmann, H. Greuner, H. Grote, M. Kammeyer, P. Kornejew, M. Laux, E. Pasch, in: 21st EPS Conference on Controlled Fusion and Plasma Physics, E. Joffrin, P. Platz, P.E. Stott, eds., Europhysics Conference Abstracts Vol. 18 B, part III, p. 1328.Google Scholar

Copyright information

© Plenum Press, New York 1996

Authors and Affiliations

  • K. Grützmacher
    • 1
  • M. I. de la Rosa
    • 1
  • J. Seidel
    • 1
  • A. Steiger
    • 1
  • G. Fußmann
    • 2
  • W. Bohmeyer
    • 2
  • D. Voslamber
    • 3
  1. 1.Physikalisch-Technische Bundesanstalt(PTB)BerlinGermany
  2. 2.Max Planck Institute of Plasma Physics (IPP), Berlin BranchAss EURATOMGermany
  3. 3.Ass. EURATOM-CEAFrance

Personalised recommendations