Fast plasma shutdown by killer pellet injection in JT-60U with reduced heat flux on the divertor plate and avoiding runaway electron generation
Fast plasma shutdown by killer pellet injection in JT-60U with reduced heat flux on the divertor plate and avoiding runaway electron generation
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DOI：
10.1088/0741-3335/39/2/008
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发表时间：
1997-02
影响因子：
2.2
通讯作者：
R. Yoshino;T. Kondoh;Y. Neyatani;K. Itami;Y. Kawano;N. Isei
中科院分区：
文献类型：
--
作者：
R. Yoshino;T. Kondoh;Y. Neyatani;K. Itami;Y. Kawano;N. Isei
杀手颗粒是一种杂质颗粒，被注入托卡马克等离子体中，以终止放电而不会对托卡马克机器造成严重损坏。在 JT-60U 中，氖冰粒已被注入 OH 和 NB 加热等离子体中，并且已证明无需大的垂直位移即可快速关闭等离子体。通过杀伤弹注射 (KPI)，偏滤器板上的热脉冲已大大减少，但仍观察到持续时间较长的低功率热通量尾部。偏滤器板上的总能量随着热通量尾部的延长而增加，因此通过缩短尾部来降低总能量。在 KPI 后和/或等离子体电流淬灭的后期阶段观察到失控电子 (RE) 的产生。然而，当激发大的磁扰动时，可以避免 RE 的产生。这些实验结果清楚地表明，KPI 是一种可靠的快速关闭方法，可避免大的垂直位移、减少偏滤器板上的热通量并避免（或最小化）RE 产生。
A killer pellet is an impurity pellet that is injected into a tokamak plasma in order to terminate a discharge without causing serious damage to the tokamak machine. In JT-60U neon ice pellets have been injected into OH and NB heated plasmas and fast plasma shutdowns have been demonstrated without large vertical displacement. The heat pulse on the divertor plate has been greatly reduced by killer pellet injection (KPI), but a low-power heat flux tail with a long time duration is observed. The total energy on the divertor plate increases with longer heat flux tail, so it has been reduced by shortening the tail. Runaway electron (RE) generation has been observed just after KPI and/or in the later phase of the plasma current quench. However, RE generation has been avoided when large magnetic perturbations are excited. These experimental results clearly show that KPI is a credible fast shutdown method avoiding large vertical displacement, reducing heat flux on the divertor plate, and avoiding (or minimizing) RE generation.