Investigation of the particle accumulation effects on the power exhaust of snowflake minus divertor on HL-2M tokamak by SOLPS-ITER

摘要

To solve the power exhaust handling challenge, meanwhile maintaining acceptable divertor target erosion, the snowflake divertor (SFD) is proposed on HL-2M tokamak. In this work, simulations are carried out by using scrape-off layer plasma simulation code SOLPS-ITER to understand the advantages of SFD on plasma detachment, with emphasis on effects of the magnetic configuration on the neutral and impurity particles transport. Two magnetic configurations, i.e. the standard divertor (SD) and SFD, are chosen for comparison. By increasing the upstream plasma density, the simulation reveals the outer target of SFD reaches plasma detachment at much lower density than that of SD. The reason lays to that SFD can enhance the accumulation of neutral particles and carbon impurity in divertor region, thus increase divertor power radiation and divertor impurity screening capabilities. The target shape combined with the magnetic configuration also plays important role in neutral and impurity accumulation and transport. Further analysis of the roles of deuterium and lower charge-state carbon on the power radiation in divertor region is presented. Finally, the performance of SFD on the divertor plasma with the increasing input power is also simulated and discussed, which is informative for the future fusion device.