Speaker
Description
Maintaining plasma performance stability and enhancing equipment durability during the long-term KSTAR experimental campaign is crucial. To achieve these goals, removing contaminants attached to the inner wall of the tokamak device is essential. Among various wall cleaning methods, Glow Discharge Cleaning (GDC) is one of the most effective techniques. At KSTAR, GDC is typically conducted before experiments, usually in the morning, or periodically. The wall reference shot (ohmic discharge) is used as a baseline to assess the wall condition and compare it with that of the previous day, prior to starting an experiment. In parallel, the electron temperature of the plasma is regularly monitored using Electron Cyclotron Emission (ECE) diagnostics. This presentation outlines a methodology for tracking wall conditions after GDC, employing ECE measurements along with average plasma density data from daily wall reference discharges. Additionally, the effectiveness of the GDC process is assessed weekly by comparing the diamagnetic energy and neutral gas pressure. A comparative analysis of GDC performance under carbon and tungsten divertor environments is also provided.
This work was supported by the R&D programs of “High Performance Tokamak Plasma Research & Development” (EN2501) through the Korea Institute of Fusion Energy (KFE) funded by the Government funds, Republic of Korea.