Fast radiation dynamics during ELMs on TCV

Total radiative powers measured by AXUV diode based bolometer cameras have been measured in lower single null, third harmonic electron cyclotron resonance (X3 ECR) heated TCV ELMing H-mode discharges. Although, the non-flat spectral response of the diodes means that total radiated powers can be in error by as much as a factor 2, with time resolution on the order of several microseconds, the cameras can resolve plasma radiation dynamics on the ELM timescale. Observations show that: (i) most of the radiation comes from the divertor and outer midplane regions, (ii) about 70% of the ELM induced radiation occurs in the first third of the ELM cycle and (iii) only a maximum of ∼8% of the ELM energy is lost through radiation.