Time-dependent measurements of the B, C, N, and O Lyman-$\alpha$ emission

POSTER

Abstract

The X-ray and Extreme Ultraviolet Spectrometer (XEUS) has been used to monitor the line emission from various impurity ions on NSTX, in particular the K-shell emission of heliumlike and hydrogenlike B, C, N, and O. While C VI typically dominates the spectrum, unusually strong emission from N VII has been observed in multiple disharges during the past run campaign. In this case, the nitrogen concentration can exceed that of carbon by an order of magnitude. Time-dependent measurements show that the nitrogen concentration builds up over the course of the discharge and coincides with a build up of boron. In a few cases we observed several unknown lines. These are clearly lines from heavy impurities, possibly molybdenum. Some of these lines can be explained by the emission from Ti XIII.

*This work was performed under the auspices of the U.S. DOE by UC-LLNL under contract W-7405-Eng-48 and by PPPL under contract DE-AC02-76CHO3073.

Authors

  • P. Beiersdorfer

    • LLNL
    • Lawrence Livermore National Lab

  • M.-F. Gu

    • LLNL

  • M. Bitter

    • PPPL

  • K.W. Hill

    • PPPL

  • R. Kaita

    • PPPL

  • Henry W. Kugel

    • PPPL
    • Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543
    • Princeton Plasma Physics Laboratory

  • L. Roquemore

    • PPPL
    • Princeton University

  • J.K. Lepson

    • UC Berkeley