Kinetic modelling of divertor fluxes during ELMs in ITER and effect of in/out divertor plasma asymmetries

ITERにおけるELM時のダイバータ熱流の運動論的モデリングとダイバータ非対称性の効果

細川 哲成*; Loarte, A.*; Huijsmans, G. T. A.*; 滝塚 知典*; 林 伸彦

Hosokawa, Masanari*; Loarte, A.*; Huijsmans, G. T. A.*; Takizuka, Tomonori*; Hayashi, Nobuhiko

Particle and energy fluxes to plasma facing components (PFCs) during uncontrolled edge localized modes (ELMs) are expected to unacceptably shorten the PFCs lifetime in ITER. Modelling of typical edge plasma conditions between and during ELMs has been carried out with 1D and 2D PARASOL particle-in-cell code. 1D simulations showed that both the total energy deposited by ELMs at the divertor being larger at the hotter/lower recycling divertor (outer divertor for grad-B direction favourable for H-mode access), which is contrary to experimental observations. This is due to large thermoelectric currents between two divertors. 1D simulations where one divertor target is set to be floating leading to a large reduction of thermoelectric currents showed an increase of the ELM heat and energy deposition at the colder/higher recycling divertor (inner divertor with favourable direction) but the degree of in/out asymmetry is smaller than in the experiment. Further studies have been carried out with 2D PARASOL to study effects of plasma drifts on the asymmetry. 2D simulations showed that for the favourable direction the ELM energy flux is predominantly deposited at the inner divertor while for the unfavourable direction it is at the outer divertor, which is in agreement with experimental findings.