Tungsten in Sight: Visible Light Active Spectroscopy of High-Z Emission in W7-X

POSTER

Abstract

Spectroscopic measurements of impurity line emission provide insight into the time evolution of impurity densities in magnetically confined fusion plasmas, enabling the inference of diffusion and convection profiles that can be compared with theory predictions. This work presents new charge exchange observations of high-n tungsten line emissions in the Wendelstein 7-X stellarator. The observed lines, located in the visible wavelength range, are identified using the relativistic Rydberg formula and enable detailed monitoring of impurity charge states spanning from q = 21 to q = 47. A universal scaling law was employed to estimate the charge exchange effective emission coefficients for these high-n transitions, which are critical for reconstructing impurity density profiles from the measured light intensities. These reconstructed profiles can then be compared with synthetic profiles from the pySTRAHL transport solver, allowing for the inference of tungsten diffusion and convection coefficients that facilitate studies of high-Z impurity transport behavior in W7-X.

Acknowledgments. Work supported by US DOE Grant No. DE-SC0021972.

*Acknowledgments. Work supported by US DOE Grant No. DE-SC0021972.This work was carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200—EUROfusion) and by the U.S. Department of Energy under Contract No. DE-SC0020990. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.

Presenters

  • Silvia Peiro

    • University of Wisconsin-Madison
    • University of Wisconsin - Madison

Authors

  • Silvia Peiro

    • University of Wisconsin-Madison
    • University of Wisconsin - Madison

  • Shawn Karl Simko

    • University of Wisconsin - Madison

  • Colin Swee

    • University of Wisconsin - Madison

  • Mark D Nornberg

    • University of Wisconsin - Madison

  • Thilo Romba

    • Max Planck Institute for Plasma Physics
    • Max Planck Insitute for Plasma Physics

  • Oliver Ford

    • Max Planck Institute for Plasma Physics
    • Max Planck Institute for Plasma Physics, Greifswald, Germany
    • Max-Planck-Institute for Plasma Physics (IPP Greifswald)

  • Thomas Wegner

    • Max Planck Institute for Plasma Physics

  • Engrhyt Rattanawongnara

    • Max Planck Institute for Plasma Physics

  • Benedikt Geiger

    • University of Wisconsin - Madison