EFDA-JET-CP(07)03/51

ELM Triggering by Local Pellet Perturbations at JET

Experimental investigations performed at ASDEX Upgrade showed that pellet pacing can raise the ELM frequency and reduce the power load on the divertor per ELM. With the available injection system, almost a doubling of the ELM frequency and according mitigation has been demonstrated. Hence, pellet pacing can be considered as a potential tool for solving problems expected for ITER type-I ELM standard scenarios. Under the expected plasma conditions, scaling predicted power flux densities during intrinsic ELMs may be several times above the threshold required for a safe and enduring divertor operation. Based on the established stepladder concept of AUG-JET-ITER, the ITER size can be approached by investigating pellet ELM triggering at JET. A main aim was to explore under which conditions ELMs can be triggered, when and where the pellet trigger is imposed and what would be the minimum required size for pacing pellets. It is ultimately this value that determines the usefulness of the pellet pacing tool.
Name Size  
EFDC070351 924.96 Kb