König R, Cantarini J, Dreier H, Erckmann V, Hildebrandt D, Hirsch M, Kocsis G, Kornejew P, Laux M, Laqua H, Pasch E, Recsei S, Szabó V, Thomsen H, Weller A, Werner A, Wolf R, Ye M Y, Zoletnik S
Euratom Association, Max-Planck-Institut fur Plasmaphysik, Wendelsteinstr. 1, 17491 Greifswald, Germany.
Rev Sci Instrum. 2008 Oct;79(10):10F337. doi: 10.1063/1.2964998.
The stellarator Wendelstein 7-X will allow for quasicontinuous operation with the duration only being limited to two 30 min discharges per day, at a continuous heating power of 10 MW electron cyclotron resonance heating (ECRH) at 140 GHz, by the capacity of the cooling water reservoir. This will result in high thermal loads on all plasma facing components of 50-100 kW/m(2) from radiation alone and of up to about 500 kW/m(2) on components additionally exposed to convective loads. In high density scenarios toroidally varying ECRH stray radiation levels of 50-200 kW/m(2) need to be coped with, requiring careful material selection and different shielding and hardening techniques. Furthermore, a gradual buildup of coatings on plasma facing optical components, which without any measures being taken, would lead to high transmission losses already within a few days of long pulse operation (equivalent to about 1 year of operation in pulsed devices like JET or ASDEX-upgrade) and therefore needs to be prevented as much as possible. In addition in situ cleaning as well as absolute calibration techniques need to be developed for all plasma facing optical systems. Here we report about some of our efforts to find, for various types of diagnostics, ways to cope with these adverse effects. Moreover, we give a few examples for individual diagnostic specific issues with respect to quasicontinuous operation, such as the development of a special integrator for the magnetic diagnostics as well as special interferometer types which can cope with unavoidable vibrations and slow path length changes due to, e.g., thermal expansion of the plasma vessel.
仿星器文德尔施泰因7-X将能够进行准连续运行，其持续时间仅受限于每天两次30分钟的放电，通过冷却水箱的容量，在140吉赫兹下以10兆瓦的连续电子回旋共振加热（ECRH）功率运行。这将导致所有面向等离子体部件上仅由辐射产生的高热负荷为50 - 100千瓦/平方米，而额外承受对流负荷的部件上的热负荷高达约500千瓦/平方米。在高密度情况下，需要应对环形变化的50 - 200千瓦/平方米的ECRH杂散辐射水平，这需要仔细选择材料以及采用不同的屏蔽和硬化技术。此外，面向等离子体的光学部件上的涂层会逐渐积累，如果不采取任何措施，在长脉冲运行的几天内（相当于在JET或ASDEX升级等脉冲装置中运行约1年）就会导致高传输损耗，因此需要尽可能防止这种情况。此外，需要为所有面向等离子体的光学系统开发原位清洁以及绝对校准技术。在此，我们报告我们为各种诊断类型寻找应对这些不利影响方法所做的一些努力。此外，我们给出一些关于准连续运行的个别诊断特定问题的示例，例如为磁诊断开发一种特殊积分器以及能够应对由于等离子体容器热膨胀等不可避免的振动和缓慢光路变化的特殊干涉仪类型。
