Impact of molecules on power balance in DIII-D low-confinement mode discharges

Edge Physics Forum

  • Datum: 23.01.2019
  • Uhrzeit: 15:30 - 16:30
  • Vortragende(r): Mathias Groth
  • Aalto University
  • Ort: Garching
  • Raum: Seminarraum D3

The Extreme Ultraviolet (EUV) emission in DIII-D high-recycling Ohmic plasmas was measured to be dominated by Ly-alpha emission, and emission from low-to-medium carbon charge states. (These findings are consistent with those from 1990s.) The EUV molecular bands (Lyman-Werner bands) are spectrally unresolved with the present DivSPRED spectrometer, but show a broad feature at the wavelength range of the Lyman-Werner bands that contributes up to 20% to total EUV emission. In contrast, in the visible wavelength range, the measured molecular band emission was measured three orders of magnitude lower than D-alpha emission. EDGE2D-EIRENE simulations, and dedicated post-processing of standalone EIRENE simulations for molecular emission, predict the deuterium molecular emission being 50-100x lower than in the deuterium atomic lines. These results indicate that molecular deuterium emission is a negligible contributor to the total radiative power balance in the divertor. The details of the experiments and simulations will be discussed.

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