Kasuya Naohiro, Itoh Kimitaka
National Institute for Fusion Science, Toki, Gifu, Japan.
Phys Rev Lett. 2005 May 20;94(19):195002. doi: 10.1103/PhysRevLett.94.195002. Epub 2005 May 16.
Two-dimensional structures of the electrostatic potential, density, and flow velocity near the edge of a tokamak plasma are investigated. The model includes the nonlinearity in bulk-ion viscosity and turbulence-driven shear viscosity. For the case with the strong radial electric field (H mode), a two-dimensional structure in a transport barrier is obtained, giving a poloidal shock with a solitary radial electric field profile. The inward particle pinch is induced from this poloidal asymmetric electric field, and increases as the radial electric field becomes stronger. The abrupt increase of this inward ion and electron flux at the onset of L- to H-mode transition explains the rapid establishment of the density pedestal, which is responsible for the observed spontaneous self-reorganization into an improved confinement regime.
研究了托卡马克等离子体边缘附近静电势、密度和流速的二维结构。该模型包括体离子粘性和湍流驱动剪切粘性中的非线性。对于强径向电场（H 模）的情况，在输运垒中获得了二维结构，给出了具有孤立径向电场分布的极向激波。这种极向不对称电场诱导了向内的粒子箍缩，并且随着径向电场变强而增加。在 L 模到 H 模转变开始时这种向内的离子和电子通量的突然增加解释了密度台基的快速建立，而密度台基是观察到的自发自重组为改善约束模式的原因。
