Study of D<sub>2</sub> Line Emission after Massive D<sub>2</sub> Injection into Runaway Electron Plateaus in DIII-D
POSTER
Abstract
Massive injection of D2 gas into runaway electron (RE) plateaus is of interest as a possible method to reduce the severity of RE-wall strikes in ITER, motivating the study of the physics of these RE plateaus. Measurements of visible and UV D and D2 line brightnesses in DIII-D indicate that D Ly-α is strongly (>10x) trapped. Self-consistent collisional-radiative modeling including D2 line opacity and both thermal and non-thermal electron impact indicates that the D2 band radiation is largely untrapped. This allows D2 band radiation to become the dominant (>2x) power radiation channel. The modeling indicates that D2 band radiation is caused by RE-impact excitation, with thermal electron impact nearly completely negligible. Initial fits to D2 band structures indicate rotational temperatures of order 3000 - 4000 K, reasonably (within 2x) close to kinetic temperatures predicted by a 1D diffusion model.
*Work supported by the Department of Energy under Award Number(s) DE-FG02-07ER54917, DE-AC05-00OR22725, DE-FG02-04ER54758, DE-FC02-04ER54698, DE-AC52-07N27344, DE-FG03-95ER54309, DE-FG02-04ER54744, and DE-FG02-04ER54762.
Presenters
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Eric M Hollmann
- University of California San Diego
- University of California, San Diego