Thermal properties of redeposition layers in the JT-60U divertor region
Thermal properties of redeposition layers in the JT-60U divertor region
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JT-60U 偏滤器区域中再沉积层的热特性
DOI：
10.1016/j.jnucmat.2006.01.013
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发表时间：
2006
影响因子：
3.1
通讯作者：
N. Asakura
中科院分区：
文献类型：
--
作者：
Y. Ishimoto;Y. Gotoh;T. Arai;K. Masaki;N. Miya;N. Oyama;N. Asakura
采用激光闪光法测量了JT-60 U W型偏滤器内板再沉积层的热性质，以估算偏滤器的瞬态热负荷。用扫描电子显微镜对再沉积层进行形态分析。对在最频繁撞击点附近制备的200μm厚的再沉积层样品进行了测量，结果表明：再沉积层的体积密度约为碳纤维复合材料的一半，其比热与各向同性石墨的比热大致相等，再沉积层的体积密度约为碳纤维复合材料的一半，再沉积层的比热约为各向同性石墨的一半，再沉积层的体积密度约为碳纤维复合材料的一半。（3）再沉积层的热导率比碳纤维复合材料的热导率小两个数量级。再沉积层的这种低热导率被认为是由再沉积层的低石墨化度引起的。考虑到内偏滤器上再沉积层的热特性，偏滤器热负荷和等离子体储存能量的损失之间的差异变得较小，而由于ELM的估计热负荷仍然大于损失。这可能是由热物性的极向分布引起的。
Thermal properties of the redeposition layer on the inner plate of the W-shaped divertor of JT-60U have been measured with laser flash method so as to estimate transient heat loads onto the divertor. Morphology analysis of the redeposition layer was conducted with a scanning electron microscope. Measurement of a redeposition layer sample of more than 200μm thick, which had been produced near the most frequent striking point, showed following results: (1) the bulk density of the redeposition layer is about half of that of carbon fiber composite material; (2) the specific heat of the layer is roughly equal to that of the isotropic graphite; (3) the thermal conductivity of the redeposition layer is two orders of magnitude smaller than that of the carbon fiber composite. This low thermal conductivity of the redeposition layer is considered to be caused by a low graphitization degree of the redeposition layer. The difference between the divertor heat loads and the loss of the plasma stored energy becomes smaller taking account of thermal properties of the redeposition layer on the inner divertor, whereas estimated heat loads due to the ELMs is still larger than the loss. This is probably caused by the poloidal distribution of the thermal properties.