Analysis for hydrogen particle balance of plasma-wall system in the large helical device
Analysis for hydrogen particle balance of plasma-wall system in the large helical device
复制标题
大型螺旋装置等离子体壁系统氢粒子平衡分析
DOI：
10.1016/j.jnucmat.2005.11.016
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发表时间：
2006
影响因子：
3.1
通讯作者：
O. Motojima
中科院分区：
文献类型：
--
作者：
M. Kobayashi;J. Miyazawa;S. Masuzaki;Y. Igitkhanov;R. Sakamoto;N. Ashikawa;T. Morisaki;N. Ohyabu;H. Yamada;H. Funaba;A. Komori;O. Motojima
采用零维模型分析了大型螺旋装置(LHD)中等离子体粒子、容器内中性粒子和壁上储氢量的氢粒子平衡。通过对低温泵送系统的中性气体压力、等离子体密度和泵浦速度的测量，发现壁面上残留的氢气具有短时间常数和长时间常数的解吸特性。短期脱附为1021个原子数量级，时间常数为几分钟，远小于单次抽运1022个原子的壁。在大约一个实验日的长时间尺度上，壁吸收了大量的氢，高达1024个原子。大壁面泵送的可能原因之一是第一壁面上的碳沉积层。讨论了氢气滞留对密度控制的影响。
The hydrogen particle balance of the plasma-wall system in the large helical device (LHD) is analyzed, using a zero dimensional model for plasma particles, neutrals in vessel and hydrogen inventory in wall. Based on the measurement of neutral gas pressure, plasma density and the pumping speed of the cryo-pumping system, it is found that the hydrogen retained in the wall desorbes with short and long time constant. The short term desorption is of order of 1021atoms with a time constant of a few minutes, which is much smaller than the wall pumping for one shot, 1022atoms. In a long time scale of about one experimental day, the wall absorbs significantly large amounts of hydrogen, up to 1024atoms. One of the possible reasons for the large wall pumping is a carbon deposition layer on the first wall surface. The effect of hydrogen retention on density control is also discussed.