Varela P, Silva A, Belo J H
Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
Rev Sci Instrum. 2018 Oct;89(10):10H102. doi: 10.1063/1.5036743.
The ITER plasma position reflectometry diagnostic aims to provide measurements of the edge plasma to correct or supplement the magnetics for plasma position control. It consists of five reflectometers, two of which have components installed inside the vessel. One of these systems probes the plasma from the high-field side using a bistatic array of small pyramidal horns located in the gap between two blankets. Electromagnetic simulations have shown that the blankets shape the radiation pattern and need to be considered as part of the antenna. Full-wave plasma simulations have confirmed these results and have also shown that the first-wall geometry may induce measurement errors above the required margin. To further address these issues, we manufactured a prototype of the high-field side antenna, which includes a mock-up of the blanket modules. Here, we present the results of the prototype tests, with and without the blankets, using a metallic mirror as a target. The signals reflected from the mirror are used to derive the mirror distance and assess the precision of the measurements under different arrangements. The sensitivity to the blankets' installation tolerances is also assessed by changing the antennas' position with respect to the blankets' surfaces and cut-outs.
国际热核聚变实验堆（ITER）的等离子体位置反射测量诊断旨在提供边缘等离子体的测量数据，以校正或补充用于等离子体位置控制的磁学测量。它由五个反射计组成，其中两个的部件安装在真空室内。其中一个系统使用位于两个包层之间间隙中的小型角锥喇叭双基地阵列，从高场侧探测等离子体。电磁模拟表明，包层会影响辐射方向图，需要将其视为天线的一部分。全波等离子体模拟证实了这些结果，还表明第一壁的几何形状可能会导致测量误差超出所需范围。为了进一步解决这些问题，我们制造了高场侧天线的原型，其中包括包层模块的模型。在此，我们展示了使用金属镜作为目标，有无包层情况下原型测试的结果。从镜子反射的信号用于推导镜子距离，并评估不同布置下测量的精度。通过改变天线相对于包层表面和切口的位置，还评估了对包层安装公差的敏感度。
