Predictive Outlook for Experiments Resolving Prompt vs Local Redeposition of High-Z Materials in Tokamaks*

High-Z plasma facing components redeposit within the sheath through a combination of two distinct mechanisms: prompt (or geometric-driven) and local (or sheath-driven) redeposition. Experimental efforts are needed to determine the leading-order parameters influencing prompt-vs-local trade-off, which sets the fraction of material entering the scrape-off layer. In preparation for such experiments, these leading-order parameters are isolated within the PYEAD-RustBCA-GITR coupled net erosion code using Sobol' sensitivity analysis. It is found that the magnetic-field-to-material pitch angle has comparable weight to sheath-entrance plasma conditions in setting the net erosion, which could accelerate the degradation of transient-damaged components. Validation experiments resolving prompt-vs-local trade-off under variation of this pitch angle are proposed using an isotopic coupon design with multifaceted diagnostic coverage. The measurability of these experiments is evaluated using synthetic diagnostics, and areas of needed technological and theoretical innovation are identified in order to facilitate the measurement.