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.