Thermographic power accounting in MAST

Target heat loads calculated from the infrared camera on MAST are presented. A parameter (α) is used to account for surface effects. In L-Mode discharges, the energy arriving at the targets, as calculated from the camera using a suitable choice of α, is in agreement with that calculated from Langmuir probes and that lost from the core. In H-Mode, energy balance can also be achieved both at the ELM and in inter-ELM periods, although a different value of α is required for different targets and for different power loads. This may be due to increased erosion leading to the production of dust in the plasma sheath.