Erlangen 2018 – scientific programme

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P: Fachverband Plasmaphysik

P 11: Helmholtz Graduate School - Poster

P 11.13: Poster

Tuesday, March 6, 2018, 16:15–18:15, Redoutensaal

Assessment of particle and heat loads to the upper open divertor in ASDEX Upgrade and comparison with SOLPS simulations — •Ivan Paradela Perez^1,2, Mathias Groth¹, Andrea Scarabosio², and ASDEX Upgrade Team² — ¹Aalto University, Finland — ²IPP Garching, Germany

Drifts and divertor geometry play a fundamental role in power, momentum and particle transport. An experiment has been carried out in the upper open divertor of ASDEX Upgrade to characterize their impact. Infra-red thermography measurements of the heat flux profiles in upper single-null, low confinement mode discharges in ASDEX Upgrade show that the heat loads onto the upper low-field side target increase by factors up to ∼ 8 when changing from unfavourable (B_T<0, ∇ B drift downwards) to favourable (B_T>0, ∇ B drift upwards) toroidal field directions. The evolution of the heat loads with increasing plasma current and core density is different for both field directions. Increasing plasma current has a greater impact on heat flux profiles in favourable direction while the effect of increasing core density (in attached conditions) is more pronounced in unfavourable direction. Power detachment is observed for both B_T directions. This dependence on the B_T direction of the evolution with increasing plasma current and core density of the target profiles has also been observed in the collected ion saturation current, I_sat, measured by the Langmuir probes. However, the roll-over of I_sat is only observed for B_T<0. Lower closed divertor AUG discharges and SOLPS simualtions will be used to improve the understanding of the large impact of drifts and divertor geometry.