Power deposition on misaligned castellated tungsten blocks in the Magnum-PSI and Pilot-PSI linear devices
Power deposition on misaligned castellated tungsten blocks in the Magnum-PSI and Pilot-PSI linear devices
复制标题
Magnum-PSI 和 Pilot-PSI 线性器件中未对准的齿形钨块上的功率沉积
DOI：
10.1088/1741-4326/aa8109
复制
发表时间：
2017
期刊：
影响因子：
3.3
通讯作者：
R. Pitts
中科院分区：
文献类型：
--
作者：
T. Morgan;M. A. van den Berg;G. De Temmerman;S. Bardin;D. Aussems;R. Pitts
对于ITER偏滤器的最终设计，重要的是确定是否需要对每个钨单块进行成形以消除前缘。为了帮助这一决定，两个实验中进行的线性等离子体装置，研究掠入射时错位水冷块的热负荷。首先，在Magnum-PSI线性装置中，将一系列钨块暴露于高平行热通量（26 MW m−2）氢等离子体束。这些块相对于等离子体束以4 °到7 °的斜角暴露，接近ITER偏滤器撞击点区域预期的低入射角。一个块相对于其他块垂直错位0至1.2 mm，并监测表面温度演变。将其与系统的有限元热机械模型进行比较，以研究两者之间的任何差异。还可以考虑拉莫尔轨道平滑效应的重要性，因为拉莫尔半径大于失准高度的一半。接下来，在Pilot-PSI线性装置中，以3 μ s至100 μs的角度暴露一排相同的钨块，以模拟边缘局域模（ELM）瞬变的影响，脉冲氢等离子体的峰值功率在275-625 MW m−2之间。一个块相对于其他块错位1 mm。在所有情况下，模型和实验被发现是在良好的协议（至100%），清楚地表明，光学近似的等离子体功率加载错位的边缘是适当的。一个简单的模型，包括拉莫尔平滑，其结果给出了类似的预测光学近似的温度的错位边缘，温度测量的误差内，虽然一个小的边缘温度降低计算。因此，可以得出结论，光学近似的应用通常是适当的输入物理假设的研究成形替代品。
For the final design of the ITER divertor it is important to determine whether shaping of each tungsten monoblock to eliminate leading edges is required or not. In order to aid this decision, two experiments were performed in DIFFER’s linear plasma devices to study heat loads on misaligned water cooled blocks at glancing incidence. First, a series of tungsten blocks were exposed to a high parallel heat flux (26 MW m−2) hydrogen plasma beam in the Magnum-PSI linear device. The blocks were exposed at an oblique angle between 4∘ and 7∘ with respect to the plasma beam, approaching the low angle of incidence expected in the ITER divertor strike-point regions. One block was vertically misaligned with respect to the others by a value between 0 and 1.2 mm, and the surface temperature evolution monitored. This was compared to a finite element thermo-mechanical model of the system, to investigate any discrepancies between the two. The importance of Larmor orbit smoothing effects could also be considered, as the Larmor radius was larger than half the misalignment height. Next, a row of identical tungsten blocks were exposed at an angle of 3∘ to ∼500–700 μs pulsed hydrogen plasmas of peak power between 275–625 MW m−2 in the Pilot-PSI linear device, to simulate the effect of edge localized mode (ELM) transients. One block was misaligned with respect to the others by 1 mm. In all cases, the model and experiment were found to be in excellent agreement (to ∼1%), demonstrating clearly that an optical approximation for plasma power loading on misaligned edges is appropriate. A simple model including Larmor smoothing was applied, the results of which give a similar prediction to the optical approximation for the temperature of the misaligned edges, within the error of the temperature measurements, though a small decrease in edge temperature is calculated. Therefore it can be concluded that the application of the optical approximation is generally appropriate as an input physics assumption for the study of shaping alternatives.