EFDA-JET-CP(10)05/14

ICRF Physics Aspects of Wall Conditioning with Conventional Antennas in Large-Size Tokamaks

This paper focuses on a study of the principal operation aspects of standard ICRF heating antennas in the Ion Cyclotron Wall Conditioning (ICWC) mode: (i) ability of the antenna to ignite the cleaning discharge safely and reliably in different gases including those most likely to be used in ITER ­ He, H2, D2 and their mixtures, (ii) the antenna capacity to couple a large fraction of the RF generator power (>50%) to low density (~1016-1018 m-3) plasmas and (iii) the RF power absorption schemes aimed at improved RF plasma homogeneity and enhanced conditioning effect. The ICWC discharge optimization in terms of RF plasma wave excitation/absorption resulted in successful simulation of the conditioning scenarios for ITER operation at full field (JET) and half field (TEXTOR, TORE SUPRA, ASDEX Upgrade).
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