Plasma radiation during transient events in JET

The radiation distribution during transient events is poloidally asymmetric with the radiation peaking at the inner main chamber wall during the current quench in density limit and NTM-driven disruptions. During the X-Point MARFE the radiation peaking occurs at the outer divertor target during the X-Point MARFE. Maximum of the observed "radiation peaking factor" for the disruptive current quench is less than 3 and for MARFEs of about 4.5, and of about 5 during VDEs. Radiation losses during VDEs (for the current quench alone) will increase the Be temperature to values around the melting point. The ELM radiation behaviour has been analysed in detail in the type I ELMy H-mode regime which is the baseline scenario for operation of ITER in high fusion gains. A significant part of the total ELM energy loss can be found in form of plasma radiation, located mostly in the divertor region. Large Type I ELMs with energy losses above 0.7MJ show enhanced radiation losses, which are associated with the ablation of carbon layers in the inner divertor. The ELM-induced radiation is always higher at the inner than at the outer divertor with the asymmetry increasing approximately linearly up to a total ΔW_ELM of about 0.6 MJ and decreasing for higher ΔW_ELM.