Power Fluxes to Plasma-Facing Components in ELM-Mitigated H-mode Discharges on JET

ELMy H-mode is foreseen as one of the scenarios for Q = 10 operating in ITER. The accompanying transient heat loads to the divertor are an urgent issue for both ITER and the metallic wall which is presently under construction at JET. Commonly, ELM-mitigation techniques are aiming at achieving higher ELM frequencies to benefit from the favourable inverse ELM-energy scaling, dWELM µ fELM-1. In recent JET-campaigns, Resonant-MagneticPerturbation (RMP) fields, impurity seeding and strong gas puffing have been compared as active ELM-mitigation techniques. All ELM-mitigation techniques are associated with some degradation of the pedestal pressure and subsequently reduction of confinement, typically in the order of 10-15%. The large surface temperature rise at the divertor targets during ELMs can cause deterioration of the plasma facing materials. A heat pulse onto a solid body leads to an increase of the surface temperature, which can be characterized by a so-called divertor ­heat-flux factor­hELM:
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EFDC110412 541.50 Kb