Power and particle fluxes to plasma-facing components in mitigated-ELM H-mode discharges on JET

The effect of ELM-mitigation techniques such as the use of magnetic-field perturbations, gas fuelling and impurity seeding using nitrogen has been studied. With increasing ELM frequency the divertor-heat-flux factor reduces only weakly. The heat-flux factor, which has been analysed taking into account ELM-profile broadening and strike-point movement and which is proportional to the surface-temperature rise due to the heat pulse during the ELM, decreases with confinement and pedestal pressure at the same rate for mitigated ELMs using gas fuelling and magnetic-perturbation fields. Only at very high fuelling rates of nitrogen is a drastic drop of the heat-flux factor with modest confinement reduction found.