Overview of recent experimental results on MAST

H-mode confinement in discharges with low frequency ELMs is generally consistent with the IPB98(y,2) scaling and exceeds it by a factor 1.5-2.0 in some high performance discharges where confinement times can exceed 100 ms. With optimised fuelling (inboard puffing) and magnetic configuration (connected DND) the H-mode power threshold data are in broad agreement with recent scaling laws; the low aspect ratio of MAST allows differentiation between different forms of the threshold scaling. Slight magnetic configuration changes (of the order of the ion Larmor radius) around a connected DND significantly influence H-mode access. Sawtooth triggered NTMs (3/2, 2/1) have been observed; numerical modelling of the island evolution reproduces mode behaviour well and confirms the significance of stabilising field curvature effects. Divertor power loading studies, including transient effects (e.g. due to ELMs), show a strong bias of power efflux to the outboard targets where it is more easily handled. Halo current magnitudes and asymmetries are generally small compared with conventional tokamaks; recent measurements show that the plasma behaves more as a voltage source than a current source. (author)