Metallic impurity sources behavior during ICRH in EAST

Guillaume Urbanczyk (1, 2) , X.J. Zhang (2) , L. Colas (1) , A. Ekedahl (3, 1) , S. Heuraux (4) , J. G. Li (2) , C.M. M Qin (2) , Y.P. Zhao (2) , L. Zhang (2) , X.D. D Yang (2)

1 IRFM - Institut de Recherche sur la Fusion par confinement Magnétique
2 ASIPP - Institute of Plasma Physics, Chinese Academy of Sciences
3 CEA/DSM/DRFC - Association EURATOM-CEA
4 IJL - Institut Jean Lamour

High-Z impurities production is often observed during Ion Cyclotron Range of Frequencies (ICRF) waves' injection, which are likely due to RF sheath formation on Plasma Facing Components (PFCs). Based on Extreme UV (EUV) spectrometry data, this study takes profit from the diversity of materials in the Experimental Advanced Superconducting Tokamak (EAST) to extract local information on plasma-surface interactions during ICRH (Ion Cyclotron Resonance Heating). Intensities of the different spectral lines normalized to line-integrated plasma density, exhibit different parametric dependencies over scans of ICRH and LH (Lower Hybrid) power and for different toroidal phasing between straps. Materials close and magnetically-connected to an active antenna tend to show better correlation with ICRF parameters-such as power and feeding scheme-than those which are far away or not connected. ICRF phasing however did not have significant influence on impurity sources, probably due to the absence of feedback control. It is further shown that the plasma content in impurities from divertor region (W line intensity) better correlates with the total injected power rather than with ICRF power.

Domains: Plasma Physics [physics.plasm-ph]

Guillaume Urbanczyk, X.J. Zhang, L. Colas, A. Ekedahl, S. Heuraux, et al.. Metallic impurity sources behavior during ICRH in EAST. Nuclear Materials and Energy, 2018, 17, pp.274-278. ⟨10.1016/j.nme.2018.10.008⟩. ⟨cea-02265780⟩