Numerical simulation of fueling pellet ablation and transport in the EAST H-mode discharge

Abstract

To understand the effect of injected deuterium (D) pellet on background plasma, the ablation of D pellet and the transport of D species in both atomic and ionic states in the EAST device are simulated by using a modified dynamic neutral gas shield model combined with the edge plasma code SOLPS-ITER. The simulation results show that there is a phenomenon of obvious atomic deposition in the scrape-off layer (SOL) after pellet injection, which depends strongly on the injection velocity. With increasing the injection velocity, the atomic density in the SOL decreases evidently and the deposition time is relatively shortened. Possible effects for edge localized modes (ELMs) triggering by D and Li pellets are also discussed in this work. With the same pellet size and injection velocity, the maximal perturbation pressure caused by D pellet is obviously higher. It is found that the resulting maximal perturbed pressure is enhanced remarkably when the injection velocity reduces from 300 to 100 m/s for a Φ1.6 mm pellet, which indicates that the injection velocity is important for ELM pacing. This work can provide reasonable guidance for choosing pellet parameters for fueling and ELM triggering.

Simulation of deuterium pellet ablation and deposition in the EAST tokamak with HPI2 code

“…[5][6][7][8] It is commonly used in current magnetic confinement fusion devices, such as DIII-D, [9] JT-60U, [10] HL-2A, [11] Tore Supra, [12] Alcator C-mod, [13] and EAST. [14,15] In 2012, a pellet fueling system with a frequency of 10 Hz was successfully developed for the EAST tokamak. This system produces cylindrical pellets of around 2.0 mm in both length and diameter.…”