Hannover 2010 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 20: Poster: Magnetic Confinement
P 20.2: Poster
Donnerstag, 11. März 2010, 16:00–18:00, Lichthof
Pellet launcher optimization for ELM pacing in ASDEX Upgrade — •Jill Jehl1, Gábor Kocsis2, Peter Lang3, Martin Prechtl4, Stefan Sotier1, Tamás Szepesi2, and ASDEX Upgrade Team3 — 1University of Applied Sciences, Lothstrasse 34, 80335 München, Germany — 2KFKI RMKI, EURATOM Association, P.O. Box 49, H-1525 Budapest-114, Hungary — 3MPI für Plasmaphysik, Boltzmannstrasse 2, 85748 Garching, Germany — 4Hochschule Coburg, Fakultät Maschinenbau, Friedrich-Streib-Strasse 2, 96450 Coburg, Germany
ELM mitigation by frequency pacing applying cryogenic Deuterium (D) pellet injection is a technique demonstrated at several tokamaks. However, using common fuelling pellet sizes resulted in significant additional particle throughput and according confinement reduction. Thus a pellet launcher system optimized for ELM pacing purposes will need to keep the high repetition rates and injection speed but would have to significantly reduce the pellet sizes. At ASDEX Upgrade, the existing blower gun system was modified accordingly, with repetition rates up to 80 Hz and pellet speeds up to 150 m/s but the particle inventory was lowered to 5 × 1019 atoms. Operation in this pellet size regime (diameter in the order of mm) turned out to be a challenging task trying to preserve reliable pellet production, acceleration and in particular transfer through a guiding system. We report on the re-commissioning of the modified system and the achieved performance.