Modeling lithium deposition on plasma facing components of LTX-β

The Lithium Tokamak eXperiment β (LTX-β) explores the benefits of using lithium as a plasma-facing component (PFC). The LTX-β has two lithium evaporators used to evaporatively coat the inside of the plasma-facing shells. The evaporators are located 180 degrees apart toroidally, each directly under a Quartz Crystal Microbalance (QCM), which is used to determine the thickness of the deposited lithium. Prior work has modeled lithium deposition on the shells using a point source approximation, but discrepancies remain between the model and observations. Specifically, coverage of the high field side limiting edges is not well diagnosed. This work extends the model to a surface source accounting for the effect of both the emission and deposition angle. This model facilitates an understanding of the lithium coverage of the shell and its interaction with the plasma. A comparison of the model's prediction with data collected on LTX-beta QCMs will be presented.