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11th International Congress on Plasma Physics: ICPP2002, Sydney, 2002-07-15 to 2002-07-19
Abstract:
The island divertor in the W7-AS stellarator enables access to a new NBI-heated, high density operating regime with promising confinement properties. This regime — the High Density H-Mode — displays no evident mode activity, is extant above a threshold density and characterized by flat density profiles, high energy- and low impurity-confinement times and edge localized radiation. Impurity accumulation, normally associated with ELM-free H-modes, is avoided. Quasi steady-state discharges with ñe up to 4 1020 m–3, edge radiation levels up to 90%, and partial plasma detachment at the divertor targets can be simultaneously realized.