HL－1托卡马克杂质注入实验及杂质输运特性的研究

IMPURITY INJECTION EXPERIMENTS AND STUDIES ON IMPURITY TRANSPORT BEHAVIOUR ON THE HL-1 TOKAMAK

本文给出了ＨＬ－１托卡马克在通常欧姆放电和偏压诱发Ｈ模放电条件下，脉冲注入杂质气体的实验结果以及对杂质在通常欧姆等离子体和偏压诱发Ｈ模等离子体中的输运研究结果。实验结果表明，在ＨＬ－１上偏压诱发Ｈ模等离子体中对杂质的约束性能明显优于在通常欧姆等离子体中对杂质的约束性能。杂质输运的数值模拟结果说明，无论在通常欧姆等离子体中，还是在偏压诱发Ｈ模等离子体中，杂质的输运系数都比新经典理论预计的要大得多，输运是反常的。在偏压诱发的Ｈ模等离子体中引入杂质输运“位阱”概念，能够对杂质离子约束时间长的实验现象进行很好的描述。合理地解释了在偏压杂质注入实验中杂质辐射上升时间长、衰减慢的现象。

Impurity transport has been studied on the HL-1 tokamak under the conditions of normal Ohmic discharge and H mode discharge induced by a biasing electrode. The experimental results of impurity gas injection and simulation analysis of impurity transport in both dischargs are presented in this paper. The experimental results show that the impurity confinement is much better in the H mode plasma induced by a biasing electrode than that in the normal Ohmic plasma. The impurity transport simulation results indicate that in both the normal Ohmic plasma and the H mode plasma induced by a biasing electrode, compared with neoclassical theory, the impurity transport coefficient is so high that the impurity transport is anomalous. We introduce the concept of“barrier”to account for impurity transport becoming longer in the H mode plasma. The phenomena of impurity radiation with longer rise time and slower decay time can be explained reasonably.