Migration of Micron Size Carbon Dust in the DIII-D Divertor

We studied migration of pre-characterized carbon dust in a tokamak environment by introducing about 30~mg of micron-size dust flakes (5-10~$\mu$m in diameter) in the lower divertor of \hbox{DIII-D} using the DiMES sample holder. In two separate experiments dust was exposed to strikepoint sweeps of high power lower-single-null discharges in an ELMing \hbox{H-mode} regime. When the outer strike point passed over the dust holder, 1-2\% of the total dust carbon content (equivalent to a few million of dust particles) penetrated the plasma core, raising the core carbon density by a factor of 2-3. Individual dust particles were observed moving at velocities of 10-100~m/s, predominantly in the toroidal direction consistent with the ion drag force. The observed behavior of the dust is in qualitative agreement with modeling by the DustT code.