Numerical Simulation Study of Plasma Flow in the GAMMA10/PDX End-cell Using a Fluid Code

In order to understand the effect of impurity injection into divertor plasma, a multi-fluid code was developed and applied to the region from west plug/barrier-cell to end cell in GAMMA 10/PDX. In this research, Ar is applied as impurity neutrals. To investigate the effect of impurity injection on plasma parameters, interactions between Ar impurity and hydrogen bulk plasma were included in this model. Under the condition of injecting neutral hydrogen and impurity Ar, the charge exchange loss between hydrogen ion and neutrals reaches to about 95% and the radiation loss for electron is enhanced to about 45%. Therefore, hydrogen ion and electron temperatures decrease from about 55 eV to 4 eV and 15 eV to 4 eV, respectively. The heat load on the target plate is also reduced by nearly 80% compared with the condition of low injection rate of neutral hydrogen and impurity. It is also observed that the particle flux increases with neutral density and then shows a tendency to saturate in the higher neutral density (> 2.1 × 10¹⁸ m^–3).