RETAINMENT OF GASEOUS AND TARGET PRODUCED IMPURITIES IN THE ASDEX DIVERTOR
The authors report on experiments performed to investigate the retainment capability of the divertor for gaseous recycling impurities and for metallic impurities produced by sputtering at the neutralizer plates. For quantitative analyses the experiments are simulated by a one dimensional transport code, including a simple divertor model. Previous experiments with argon and neon indicated a pronounced deterioration of the retainment during neutral beam heating in particular with the transition to the H-mode. In the experiments described we aimed for the divertor containment time tau-D, which characterizes the retainment in case of recycling impurities sputtered at the neutralizer plates has been investigated for the first time. For this purpose a fraction of 3.5 % of the neutralizer plates (Ti) in the bottom divertor has been covered with copper, a metal so far not existent in ASDEX. The flux of the copper atoms in front of the target plates as well as the copper density in the main plasma were determined by spectroscopic methods.
Bibliographic Reference: 12TH EUROPEAN CONFERENCE ON CONTROLLED FUSION AND PLASMA PHYSICS, BUDAPEST (HUNGARY), SEPT. 2-6, 1985 WRITE TO MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, 8046 GARCHING BEI MUENCHEN (GERMANY), MENTIONING REPORT IPP III/107, 1985, PP. 57-60.
Record Number: 1989124096300 / Last updated on: 1987-01-01
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