Reimerdes, HCanal, G PDuval, B PLabit, BLunt, TNespoli, FVijvers, W A JDe Temmerman, GLowry, CMorgan, T WTal, BWischmeier, M2015-03-022015-03-022015-03-02201510.1016/j.jaucmat.2014.10.076https://infoscience.epfl.ch/handle/20.500.14299/111800WOS:000358467200262Recent TCV experiments have examined the effect of the poloidal field strength in the vicinity of the x-point of diverted configurations on their ability to radiate a large fraction of the exhaust power. A larger region of low poloidal field is a key characteristic of the "snowflake" configuration, which has been proposed as an alternative divertor solution that decreases the power flux to the targets in a DEMO-size tokamak. In the investigated Ohmic discharges, increasing the plasma density and seeding neon both increased the radiated exhaust fraction up to 60-70%. In all cases, the highest radiation fraction was determined by the onset of MHD rather than a radiation instability. The experiments indicate that, while the conventional single-null configuration leads to more radiation (+10%) at higher densities, the snowflake configuration radiates more when seeding neon impurities (+15%). Extrapolation of these modest, but systematic, dependencies on the divertor geometry to reactor-relevant higher heating power and larger device size must be based on a physics model.tokamaksdivertorsnowflake divertortext::conference output::conference proceedings::conference paper