ELM mitigation by means of supersonic molecular beam and pellet injection on the EAST superconducting tokamak

Abstract

In this paper, we will present experimental results from EAST on the mitigation of edge localized modes (ELMs) using recently developed deuterium/lithium pellet injections as well as supersonic molecular beam injections (SMBI). Using a Laval nozzle, ELM mitigation with SMBI has been demonstrated in EAST in quasi-steady state. Using a D2 pellet injector, a giant ELM appears followed by a burst of high frequency ELMs at ∼300Hz with duration of a few tens of milliseconds. Furthermore, for the first time, a novel technology using a simple rotating impeller to inject sub-millimeter size lithium (Li) granules at speeds of a few tens of meters per second was successfully used to pace ELMs. These experiments indicate that, on EAST, several technologies can contribute to the database supporting ELMs control in future fusion devices, such as ITER.