The role of divertor pumping combined with full drifts in particle exhaust and divertor plasma

• Published in: Nuclear fusion 2024-08, Vol.64 (8), p.86058
• Main Authors: Zhao, Xuele, Sang, Chaofeng, Wang, Yilin, Zhang, Chen, Wang, Dezhen
• Format: Article
• Language: English
• Subjects: drift; particle exhaust; plasma detachment; pumping
• ISSN: 0029-5515; 1741-4326
• DOI: 10.1088/1741-4326/ad4ef7

The effect of drifts combined with pumping on particle exhaust is assessed using the SOLPS-ITER code package, considering full drifts. Both drift and pumping speed S can affect particle exhaust. Drifts change the neutral density by influencing plasma flow and the resulting particle recycling. This leads to the accumulation of neutral particles either far away or close to the pump opening location. The particle exhaust is enhanced as S rises. When the pump opening is positioned at the common flux region (CFR) of the outer divertor (referred to as Pump CFR/OD), particle exhaust is suppressed by drifts in forward B t , while it is enhanced by drifts in reversed B t , with fixed S . On the other hand, when the pump is situated in the private flux region (PFR) of the OD (referred to as Pump PFR/OD), particle exhaust is enhanced by drifts in both reversed and forward B t compared to the case without drifts. Moreover, the effective pumping in reversed B t is stronger than in forward B t . In the same B t direction, Pump PFR/OD has a higher effective pumping than Pump CFR/OD. Increased S results in higher particle exhaust in all B t direction and pump location cases. The plasma detachment is affected by drift, S and pump opening location, respectively. For the specified B t direction and pump opening location case, higher S suppresses plasma detachment. For identical particle exhaust rates, stronger pumping capacity can promote plasma detachment. Therefore, Pump PFR/OD can more easily achieve OD detachment than Pump CFR/OD in the same B t direction. Overall, placing the pump at the PFR side of the OD while running in reversed B t is the best option from the divertor particle exhaust and plasma detachment point of view.