Center for Energy Research, University of California of San Diego, 9500 Gilman Drive, M/C 0417, La Jolla, California 92093, USA.
Phys Rev Lett. 2011 Mar 18;106(11):115001. doi: 10.1103/PhysRevLett.106.115001. Epub 2011 Mar 15.
The first measurements of turbulent stresses and flows inside the separatrix of a tokamak H-mode plasma are reported, using a reciprocating multitip Langmuir probe at the DIII-D tokamak. A strong co-current rotation layer at the separatrix is found to precede intrinsic rotation development in the core. The measured fluid turbulent stresses transport toroidal momentum outward against the velocity gradient and thus try to sustain the edge layer. However, large kinetic stresses must exist to explain the net inward momentum transport leading to co-current core plasma rotation. The importance of such kinetic stresses is corroborated by the success of a simple orbit loss model, representing a purely kinetic mechanism, in the prediction of features of the edge corotation layer.
首次报道了在 DIII-D 托卡马克中使用往复式多尖端 Langmuir 探针测量托卡马克 H 模等离子体边缘分离区内部湍流应力和流动的结果。发现边缘分离区存在一个与主流同向的强旋转层，该旋转层先于核心区固有旋转的发展。测量得到的流体湍流应力沿速度梯度向外输运环形动量，从而试图维持边缘层。然而，为了解释导致与主流同向的核心等离子体旋转的净向内动量输运，必然存在较大的动应力。一个简单的轨道损失模型的成功证实了这种动应力的重要性，该模型代表了一种纯粹的动力学机制，可以预测边缘共旋层的特征。
