Impurity Production by the ICRF Antennas in JET

Studying the behaviour of impurities is important to understand and minimize their effects on tokamak plasma performance. A possible source of impurities is the use of Ion Cyclotron Resonance Frequency (ICRF) power. Although this phenomenon can be minimized by improved antenna design, recent development on impurities content monitoring can be used to further investigative the processes leading to this increase. More specifically, spectroscopic studies have been recently undertaken on JET in order to monitor the impurity content during the operation of the A2 ICRF antennas. In this paper, Nickel (Ni) release during ICRF heating is presented as a function of the relative phasing of the antenna straps, D2 gas injection level, plasma-strap distance, and applied ICRF power level.
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EFDC100627 1.53 Mb