Development of lithium vapor injector for boundary control

A lithium (Li) vapor injector for boundary control has been developed. A diverter covered with lithium is expected to reduce particle recycling. Recycling reduction is considered to be one of the triggers for the L–H transition. In this paper, the method of lithium dispersion is investigated under the assumption that the experiment is carried out in the Large Helical Device in National Institute for fusion Science, Japan (LHD). A performance test is performed on a prototype of the vapor injector. The amount of injected lithium was approximately 1% of the value expected from the vapor pressure data, due to the generation of lithium oxide. It is also found that nozzle temperature is quite important to suppress the Li dispersion.