A comparison of H-mode pedestal characteristics in MAST as a function of magnetic configuration and ELM type

The H-mode pedestal characteristics on MAST are measured in a variety of connected double null (CDN) and single null divertor (SND) discharges. In CDN discharges the edge density pedestal width in spatial co-ordinates is similar on both the high and the low field sides suggesting that the width may be determined by neutral penetration. However, in SND discharges the density pedestal width appears to be a flux surface quantity, which suggests that the scrape-off-layer may have a role to play in determining the density pedestal width. In both CDN and SND discharges the temperature pedestal width appears to be a flux surface quantity. The pedestal characteristics and edge stability have been studied as a function of the ELM type. The edge temperature pedestal is found to have a weak dependence on rho*(pol), but increases with beta(pol) as Delta(Te) proportional to (beta(pol)) 0.5.