Disruption mitigation with high-pressure helium gas injection on EAST tokamak
Disruption mitigation with high-pressure helium gas injection on EAST tokamak
复制标题
通过 EAST 托卡马克高压氦气注入缓解干扰
DOI：
10.1088/1741-4326/aaa139
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发表时间：
2018
期刊：
影响因子：
3.3
通讯作者：
Xiao B. J.
中科院分区：
文献类型：
--
作者：
Chen D. L.;Shen B.;Granetz R. S.;Qian J. P.;Zhuang H. D.;Zeng L.;Duan Y.;Shi T.;Wang H.;Sun Y.;Xiao B. J.
高压惰性气体注入是一种很有前途的技术，可以减轻托卡马克干扰的影响。本文报道了EAST托卡马克上低z大质量注气（氦）减缓实验的结果。在EAST上开发并成功实现了一种快速阀，阀响应时间≤150 μs，可注入高达7×1022个粒子，相当于300倍的等离子体库存。在初步实验中，将不同数量的氦气注入稳定的等离子体中。可见，少量氦气（NHe→Nplasma）不能终止放电，但可以触发MHD活动。注入40倍等离子体库存杂质（NHe≃40×Nplasma）可以有效地辐射掉部分热能，使电子密度迅速增加。缓解的结果是，电流淬火时间和垂直位移都可以显著减少，而不会导致环路电压显著升高。这也降低了失控电子产生的风险。随着杂质气体注入量的增加，气体穿透时间逐渐减小，渐近线为（~ 7 ms）。此外，杂质气体射流也被注入到vde中，这对缓和稳定等离子体更具挑战性。
High pressure noble gas injection is a promising technique to mitigate the effect of disruptions in tokamaks. In this paper, results of mitigation experiments with low-Z massive gas injection (helium) on the EAST tokamak are reported. A fast valve has been developed and successfully implemented on EAST, with valve response time ⩽150 μs, capable of injecting up to 7×1022 particles, corresponding to 300 times the plasma inventory. Different amounts of helium gas were injected into stable plasmas in the preliminary experiments. It is seen that a small amount of helium gas (NHe≃Nplasma) can not terminate a discharge, but can trigger MHD activity. Injection of 40 times the plasma inventory impurity (NHe≃40×Nplasma) can effectively radiate away part of the thermal energy and make the electron density increase rapidly. The mitigation result is that the current quench time and vertical displacement can both be reduced significantly, without resulting in significantly higher loop voltage. This also reduces the risk of runaway electron generation. As the amount of injected impurity gas increases, the gas penetration time decreases slowly and asymptotes to (∼7 ms). In addition, the impurity gas jet has also been injected into VDEs, which are more challenging to mitigate that stable plasmas.