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Author(s):
V.Yu. Sergeev, K.V. Khlopenkov, B.V. Kuteev, S. Sudo, K. Kondo, F. Sano, H. Zushi, H. Okada, S. Besshou, T. Mizuuchi, K. Nagasaki, Y. Kurimoto and T. Obiki
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Title:
Recent Experiments on Li Pellet Injection into Heliotron E
Date of publication:
Aug. 1996
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Key words:
lithium pellet injection, Heliotron E, lithium pellet ablation, impurity particle behavior, wall conditioning.
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Abstract:
The Li pellets of a large size were injected into ECR heated plasmas and NBI heated plasmas of Heliotron E. The discharge behavior, pellet ablation and wall conditioning were studied. The electron pressure is doubled after injection into NBI plasma and unchanged in case of ECR heating. This may be caused by the energy exchange between electrons, thermal ions with fast ions from the neutral beam. The observed discrepancy between the experimental and modeled ablation rates may be explained by both the plasma cooling by pellet ablatant and ablation stimulated with the fast ions during NBI heated regime and fast electrons during ECR heated regime. In the preliminary experiments on wall conditioning by Li pellet injection, no improvement of plasma performance after Li pellet injection was observed in both divertor configuration and limiter configuration with the limiter radii r_L = 24-25 cm.
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