Impact of edge harmonic oscillations on the divertor heat flux in NSTX

POSTER

Abstract

Previously, ELM-free and inter-ELM divertor peak heat flux reduction induced by an edge harmonic oscillation (EHO) was observed in NSTX (K.F. Gan et al., 2017 Nucl. Fusion 57 126053). This paper introduces new analysis of the EHO impact on the divertor heat flux. It was found that enhanced edge turbulence significantly increases the divertor hear flux footprint width in NSTX, relative to ELM-free discharges. The EHO at low edge fluctuation level will significantly increase the heat flux width and decrease the divertor peak heat flux, while the EHO at high edge fluctuation level will increase the divertor peak heat flux.  It was also found that the heat flux width increased with the frequency of the EHO.

*This work was supported by the US DOE contract DE-SC0016915 (UTK).

Presenters

  • Kaifu Gan

    • University of Tennessee

Authors

  • Kaifu Gan

    • University of Tennessee

  • Travis K Gray

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Stewart J Zweben

    • Princeton Plasma Physics Laboratory

  • Eric D Fredrickson

    • Princeton Plasma Physics Laboratory

  • Rajesh Maingi

    • Princeton Plasma Physics Laboratory

  • Adam G McLean

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab
    • LLNL

  • Brian D Wirth

    • University of Tennessee
    • University of Tennessee Knoxville
    • Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996, USA; Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA