Doctoral Dissertations
Date of Award
8-2024
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Major
Energy Science and Engineering
Major Professor
David C. Donovan
Committee Members
Theodore Biewer, Livia Casali, Ezekial Unterberg
Abstract
The economic and engineering success of magnetic confinement fusion reactors significantly depends upon the optimization of plasma facing component (PFC) design. For high-Z PFCs, the critical engineering condition is minimal net erosion (i.e. gross erosion – redeposition). Here, we present a high-Z net erosion model discriminating three primary redeposition mechanisms: prompt (geometric-driven), local (sheath-driven), and far (scrape-off-layer-driven). Using these distinctions, we show modeling for high-Z net erosion in magnetic-confinement fusion over a matrix of key plasma parameters. With Sobol’ methods we assess the sensitivity of each mechanism and show that prompt-vs-local trade-off critically explains underprediction in redeposition losses of up to two orders of magnitude across magnetic-field-to-PFC pitch angles. Finally, we report a “design-of-experiment” study exploring the measurability of prompt vs local distinctions in current experimental facilities. We use a combination of synthetic diagnostics and plasma-parameter optimization to propose an isotopic method of measurement by exploiting robust in situ and ex situ techniques. In principle, this approach provides a ready path forward for improving and validating PFC models needed to target optimal regimes of PFC design in future reactors.
Recommended Citation
Easley, Davis C., "Prompt vs Local Redeposition: Model Refinement and Experimental Design for Understanding High-Z Net Erosion in Magnetic Confinement Fusion. " PhD diss., University of Tennessee, 2024.
https://trace.tennessee.edu/utk_graddiss/10452