Simulation of impurity transport in the peripheral plasma due to the emission of dust in long pulse discharges on the Large Helical Device

Investigation of dust shielding effect of intrinsic ergodic magnetic field line structures in the peripheral plasma in the large helical device

“…An impurity transport simulation by a fully three‐dimensional peripheral plasma fluid code (EMC3‐EIRENE) coupled with a dust transport simulation code (DUSTT) shows that the plasma discharges are interrupted by much lower amounts of iron dust emission from the helical coil and can compared to the carbon dust emission from the divertor region . Our simulation proves that the effect of the strong plasma flow in the divertor legs prevents the carbon dust from penetrating into the main plasma.…”

“…The ionization/recombination coefficients of the iron atoms and those of the ions, as well as the radiation power, are derived from database on the atomic data and analysis structure (ADAS) . A converged solution of plasma parameter profiles such as the plasma density and temperature, the plasma flow velocity, the radiation power, and the impurity ion density are obtained by an iterative calculation scheme between the two simulation codes . The input parameters for the simulation are the plasma heating power and the plasma density at the LCFS ( P LCFS and n e LCFS ).…”

Remobilized dust dynamics and inventory evolution in ITER-like start-up plasmas

“…Such remobilized metallic particles moving inside the plasma are a potential source of high-Z impurities through vaporization, which may then cause radiation losses sufficient to result in premature discharge termination. Radiative collapse due to metallic dust has been observed in fusion devices [37,38] and predicted theoretically for ITER-like steady-state discharges [39].…”

Full‐torus impurity transport simulation for optimizing plasma discharge operation using a multi‐species impurity powder dropper in the large helical device

“…The magnetic field lines are bundled into four divertor legs which deviate from the outermost surface of the ergodic layer [4]. On applying the IPD to the plasma discharge experiments, there is a concern that the dropped impurity powder particles (dust) cannot reach the ergodic layer because of the effect of the plasma flow in the divertor legs which can perturb the original free-fall trajectories of the dust particles [5]. The trajectories are investigated using a three-dimensional peripheral plasma fluid code (EMC3-EIRENE) [6][7][8] coupled with a dust transport simulation code (DUSTT) [9][10][11] in the LHD full-torus geometry.…”