Induced tungsten melting events in the divertor of ASDEX Upgrade and their influence on plasma performance
Induced tungsten melting events in the divertor of ASDEX Upgrade and their influence on plasma performance
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DOI：
10.1016/j.jnucmat.2010.12.229
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发表时间：
2011-08
影响因子：
3.1
通讯作者：
K. Krieger;T. Lunt;R. Dux;A. Janzer;A. Kallenbach;H. W. Müller;R. Neu;T. Pütterich;V. Rohde
中科院分区：
文献类型：
--
作者：
K. Krieger;T. Lunt;R. Dux;A. Janzer;A. Kallenbach;H. W. Müller;R. Neu;T. Pütterich;V. Rohde
使用机械手系统将1×1×3mm的钨棒暴露在ASDEX Upgrade的外偏滤器板处。在H模式放电中，通过将外撞击点向W棒位置移动来诱导W棒的受控熔化。用快速照相机系统记录了喷射出的W液滴的可见光发射。在约束等离子体中的钨浓度的增加相比，由W激光烧蚀到外部主室边界等离子体引起的。由此得到的偏滤器保持率表示为偏滤器源穿透钨芯的概率与主室源穿透钨芯的概率之比为100。喷射液滴被发现总是在等离子体流的一般方向上移动。测量的液滴加速度的大小表明，液滴主要受到火箭力和摩擦力。典型的初始液滴尺寸可以从液滴光发射的时间演变推断为约100μm。
Tungsten rods of 1×1×3mm were exposed at the outer divertor plate of ASDEX Upgrade using a manipulator system. Controlled melting of the W-rod in H-mode discharges was induced by moving the outer strike point towards the W-rod position. Visible light emission of ejected W droplets was recorded by fast camera systems. The resulting increase of tungsten concentration in the confined plasma was compared to that induced by W laser ablation into the outer main chamber boundary plasma. The resulting divertor retention expressed as ratio of tungsten core penetration probability from a divertor source to that of a main chamber source is ≈100. Ejected droplets are found to move always in general direction of the plasma flow. The measured magnitude of droplet acceleration shows that droplets are mainly subject to rocket forces and friction forces. Typical initial droplet size can be inferred from the time evolution of the droplet light emission to be ⩾100μm.