Heating and ablation of tokamak graphite by pulsed nanosecond Nd-YAG lasers
Heating and ablation of tokamak graphite by pulsed nanosecond Nd-YAG lasers
复制标题
DOI：
10.1063/1.2721750
复制
发表时间：
2007-04
影响因子：
3.2
通讯作者：
A. Semerok;S. Fomichev;J. Weulersse;F. Brygo;P. Thro;C. Grisolia
中科院分区：
文献类型：
--
作者：
A. Semerok;S. Fomichev;J. Weulersse;F. Brygo;P. Thro;C. Grisolia
介绍了热核托卡马克石墨瓦激光加热和烧蚀的实验结果。使用两种脉冲Nd-YAG激光器（20 Hz重复频率，5 ns脉冲持续时间和10 kHz重复频率，100 ns脉冲持续时间）进行烧蚀测量。测定了未暴露于等离子体的Tore Supra托卡马克石墨瓦（背面）的烧蚀阈值（5ns时为1.0±0.5 J/cm2, 100ns时为2.5±0.5 J/cm2）。采用高重复频率Nd-YAG激光器（10 kHz， 100 ns脉冲持续时间）和研制的高温计系统对石墨加热进行了测量。观察到激光加热石墨表面的一些意想不到的特征。这可以用石墨表面薄层的存在来解释，薄层的性质与石墨体的性质不同。建立了具有不完全粘附层的石墨的激光加热和近阈值烧蚀的理论模型来解释实验结果。
The results on laser heating and ablation of graphite tiles of thermonuclear tokamaks are presented. Two pulsed Nd-YAG lasers (20 Hz repetition rate, 5 ns pulse duration and 10 kHz repetition rate, 100 ns pulse duration) were applied for ablation measurements. The ablation thresholds (1.0±0.5 J/cm2 for 5 ns and 2.5±0.5 J/cm2 for 100 ns laser pulses) were determined for the Tore Supra tokamak graphite tiles (backside) nonexposed to plasma. The high repetition rate Nd-YAG laser (10 kHz, 100 ns pulse duration) and the developed pyrometer system were applied for graphite heating measurements. Some unexpected features of laser heating of the graphite surface were observed. They were explained by the presence of a thin surface layer with the properties different from those of the bulk graphite. The theoretical models of laser heating and near-threshold ablation of graphite with imperfectly adhered layer were developed to interpret the experimental results.