Wall Conditioning by ECRH and GDC at the Wendelstein 7-X Stellarator
نویسندگان
چکیده
Wall conditioning in magnetic controlled fusion devices is a common tool to improve plasma performance and discharge reproducibility [1]. It will be relied upon in the next W7-X operation phases (OP1.2 in 2017-2018 and OP2 starting in 2020) to control the surface state of the plasmafacing components (PFC) with the eventual aim of providing access to continuous discharge operation [2]. The super-conducting stellarator W7-X keeps its magnetic field charged during the experimental days. Therefore conventional wall conditioning by glow discharges cannot be routinely used and alternatively RF-based wall conditioning scenarios are foreseen. The multimegawatt ECRH system [3], operational during the first operation campaign (OP1.1) of W7-X, is well suited for this purpose, since in a stellarator the confining magnetic field already exists in the vacuum. The confined ECRH plasma could be sufficiently dense and hot to provide good absorption of ECRH power minimizing stray radiation. Conditioning by ICRH discharges will become available in the next operation campaign OP1.2.
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