Radiation distribution and energy balance during type-I ELMs in ASDEX Upgrade

Edge localised modes (ELMs) are a serious concern for plasma facing components in next generation tokamaks. Due to the limited capabilities of the commonly used bolometers reliable radiation data are generally only available with a time resolution of a few milliseconds, which is much larger than the power deposition time of type-I ELMs. Therefore an improved evaluation algorithm for bolometric data has been developed which allows to calculate the radiated energy on type-I ELM relevant timescales and to tomographically reconstruct the spatial distribution of the radiated energy during an ELM. This method has been used to investigate radiation during type-I ELMs in various plasma configurations. The spatial distribution of the radiated energy during an ELM shows that radiation losses are mainly located in the divertor. Up to 40% of the ELM energy loss are found as radiation. The energy balance is nearly fulfilled in most cases.