44th Annual Meeting of the Divison of Plasma Physics, Novembro de 2002, Orlando, USA

	ELM Control by Enhance Radiation in JET Pasmas
	M.F.F. Nave, T.C. Jones, K. Lawson, P. Lomas, G. Mathews, P. Andrew, G. Saibene, S. Jachmich, L.C. Ingesson, J. Ongena, J. Strachan e os contributos da EFDA-JET Workprogramme
	Resumo
	Impurity injection was used to control plasma edge conditions in a variety of JET plasmas. Enhanced radiation decreased the power conducted into the confinement barrier, and reduced the pedestal temperature. The pedestal pressure decreased, leading to improved kink and ballooning stability. In the hot-ion H-mode regime, Argon, Xenon and Krypton injection caused a delay of the first giant ELM. In optimized shear plasmas, Argon or Krypton injection maintained a low pedestal pressure, preventing the formation of ELM-free periods, and type I ELMs. In steady ELMy H-Mode plasmas, impurity injection was as effective as Deuterium puffs in provoking a transition from type I to type III ELMs. Similar behavior was observed in Mark II plasmas with Nitrogen and Neon seeding and in recent RI experiments with Argon at low and high triangularity. High performance was obtained in type I ELMy H-Modes. Impurity seeding reduced the ELM frequency and at large radiation lead to intermittent ELM-free periods. The ELM amplitude and related power losses were reduced compared to unseeded discharges