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M. Kobayashi , S. Morita , C.F. Dong , Y. Feng, S. Masuzaki , M. Goto , T. Morisaki , H.Y.Zhou , H. Yamada and the LHD experimental group Edge Impurity Transport Study in Stochastic Layer of LHD and Scrape-off Layer of HL-2A
Edge-Core Interaction Revealed with Dynamic Transport Experiment in LHD
Date of publication:
22 IAEA Fusion Energy Conference, EXD/6-5Ra
Edge impurity transport has been investigated in the stochastic layer of LHD and the scrape-off layer (SOL) of HL-2A, as a comparative analysis based on carbon emission profile measurement and threedimensional edge transport simulation. The 3D simulation predicts impurity screening effect in the both devices, but with different behavior against collisionality and the impurity source location. The difference is attributed to topological effects of the field lines in the stochastic layer and X-point poloidal divertor SOL. The carbon emission (CIV) profile in the stochastic layer of LHD shows clear signature of impurity movement towards downstream at high density range, in reasonable agreement with the 3D code simulation predicting impurity screening. Comparison of CIV profile measurements in HL-2A with the modelling is not straightforward, and a further assessment is necessary on the impurity source distribution/amount in the divertor plate and first wall, in order to interpret the experimental observations.
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