Simulation study on global migration of locally generated impurity in JT-60U

The transport of carbon and neon particles locally emitted from plasma facing components under the JT-60U L-mode plasma condition is investigated by the integrated divertor code SONIC. In this analysis, an impurity point source emitting a small amount of impurity particles functioning as tracers at the divertor target is added into previously calculated background plasma with changing point source location. For carbon, 60 percent or more of the emitted carbon particles from the attached area in inner/outer divertor target return and deposit onto the same inner/outer divertor target, respectively. For emitted carbon particles from the detached area, the ratio of deposition onto the divertor dome increases to around 50 percent. For neon impurity, 80 percent or more of emitted neon particles from the separatrix on the outer and inner divertor target are transported onto the outer and inner divertor target until first recycling experience, especially for low density cases. After the sequence of recycling experiences, the spatial neon density profile becomes similar, from whichever point source locations, outer or inner divertor neon is emitted. Results indicate that the location of the impurity source is not important for non-sticky impurities, such as neon. To control radiation profile by impurity source location, e.g., impurity puffing, non-sticky impurity is not effective.