Temporal evolution and spatial distribution of dust creation events in Tore Supra and in ASDEX Upgrade studied by CCD image analysis

摘要

Images of wide-angle visible standard CCD cameras contain information on dust creation events (DCEs) that occur during plasma operations. Analysing the straight line-like dust traces in the shallow volume of scrape-off layer along the vacuum vessel, caused by plasma-dust interaction, the database on the DCEs is built. The database provides short/long term temporal evolution and spatial distribution of origins of DCEs in fusion devices. We have studied the DCEs of CIMES (2006) and DITS (2007) Tore Supra (TS) campaigns, and the DCEs of the 2007 ASDEX Upgrade (AUG) campaign. The results from the TS CIMES campaign show different patterns of DCEs meaning different plasma-wall interaction depending on power coupling. The TS DITS campaign indicates that dusts may be an operational limit if a fixed plasma operation scenario is used repeatedly. Different behaviours of DCEs between the carbon limiter machine and the full tungsten divertor machine are found, which is important for next generation fusion machines like ITER.