Modeling of dust transport and impact on fusion edge plasmas

Summary form only given. Recent experiments demonstrated that dust penetrating into fusion plasma edge can significantly affect the plasma performance due to dust originated impurities. It is also feasible that intentional dust injection can be used for control of edge plasma parameters, wall conditioning and emergency plasma shutdown. In this work, we model dynamics of dust injected in tokamak edge plasmas with different rates and the effects of dust originated impurities on the plasmas using the coupled DUSTT/UEDGE code. The code can simulate as individual trajectories of dust particles, as well as self-consistently coupled transport of plasma and continuously injected dust in tokamak edge. Injection of carbon, tungsten and lithium dust in NSTX and ITER tokamaks are modeled. The code validation was performed using 3-D dust trajectories measured on NSTX. The modeling demonstrates that dust injection with rates of several 10mg/s in NSTX can significantly affect the edge plasma density and temperature profiles, plasma flows and pressure gradients. The simulations also show that achieving similar effects in ITER requires much higher rates of dust injection, up to a few g/s. The possibility of divertor heat load reduction using injection of dust in tokamak plasmas is demonstrated. The differences between the dust injection and the injection of equivalent amounts of gaseous impurities in the edge plasmas are discussed.