Abstract Details
Abstracts
Author: Ray Mattes
Requested Type: Consider for Invited
Submitted: 2026-03-10 15:24:06
Co-authors: L. Casali, T. Osborne, A. Leonard,
Contact Info:
University of Tennessee Knoxville
2484 Sunrise Ridge Way
Knoxville, Tennessee 37921
United States
Abstract Text:
SOLPS-ITER modeling of dedicated H-mode hydrogen and deuterium experiments at DIII-D has been conducted revealing significant effects of the main ion mass in the edge plasma under a range of divertor regimes. In the experiment, systematically higher ne,sep in hydrogen is found for similar fueling rates. When ne,ped is matched in hydrogen and deuterium as are the ne and Te pedestal structures, although the target conditions deviate strongly from each other even under these conditions. Pedestal stability and neutral fueling analysis shows they are not sufficient to explain the pedestal differences between isotopes. Hydrogen and deuterium density ramps demonstrate a 20% higher ion current at detachment onset in hydrogen which occurs at similar upstream densities for both isotopes. The characteristics of target heat flux and divertor radiation are found to change significantly in each divertor operational regime with isotope mass. Interpretive SOLPS-ITER modeling of the experimental density scans, including particle drifts and matched upstream profiles, has been conducted. Alterations to the ionization source distribution with isotope mass contributes to a higher nesep in hydrogen for a given fueling rate. A significant portion of this particle source occurs near the midplanes. The source on the high field side trends in opposite directions for both isotopes through the density scan, indicating a strong role of drift-induced divertor asymmetries. A much cooler inner target allows for variations in the ratio of reflected atoms to desorbed molecules with the isotope mass to be expressed at high densities, resulting in this deviation. Further, plasma-molecule interactions are found to play less of a role in momentum losses in detached conditions for hydrogen, although these losses are somewhat compensated for by other mechanisms. Initial modeling with tritium, as well as the implementation of tungsten walls, demonstrates that the interplay between isotope mass and the wall
Characterization: 2.0
Comments: