Modeling powder injection experiments in LHD with the DIS and DUSTT codes

Recent boron powder injection experiments performed on the Large Helical Device (LHD) have shown beneficial effects on plasma performance through real-time wall conditioning [1, 2]. Several diagnostic measurements and modeling with EMC3-EIRENE and DUSTT codes suggest deeper penetration of B powder grains into low-density plasmas, making them a better candidate for boronization applications [3,4]. Correct modeling of the dust trajectory is fundamental for the correct interpretation of this kind of experiment. To this end, the Dust Injection Simulation (DIS) was recently developed, with the capability of handling 3D, time-varying plasma backgrounds [5]. To determine the dust grain trajectory, DIS solves Newton's equation, along with the equations for dust electric charge, temperature, and evaporation rate. Here we present the comparison of results gained from DIS and from the more established DUSTT code [6], using EMC3-EIRENE [7,8] simulations from the LHD serving as the 3D plasma background. Preliminary results show a qualitative agreement between the two codes.