Divertor heat flux mitigation by using supersonic molecular beam injection in the HL-2A tokamak

Abstract

Reduction in the power load deposited onto the divertor target plates is achieved with supersonic molecular beam injection (SMBI) fuelling. The largest reduction in the heat flux profiles occurs at the outboard divertor separatrix strike point, while the heat flux far from the strike point almost keeps constant. Most of this reduction in the divertor heat flux is accompanied by an enhanced plasma radiation. Especially, a partially detached divertor regime is observed with multi-pulse SMBI. Moreover, the divertor heat flux is also mitigated strongly with SMBI in ELMy H-mode plasmas. During this mitigation period, the large-scale fluctuations are suppressed while the small-scale fluctuations increase. These results demonstrate that SMBI technique can be considered as one of the technique tools for mitigating the power load deposited onto the divertor target.