Collisionless kinetic-fluid model of zonal flows in toroidal plasmas
Collisionless kinetic-fluid model of zonal flows in toroidal plasmas
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DOI：
10.1063/1.2435329
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发表时间：
2006-12
影响因子：
2.2
通讯作者：
H. Sugama;Tomo-Hiko Watanabe;W. Horton
中科院分区：
文献类型：
--
作者：
H. Sugama;Tomo-Hiko Watanabe;W. Horton
提出了一种描述托卡马克中纬向流无碰撞时间演化的新的动流模型。在新的纬向流封闭关系中，平行热通量用短时间演化部分和长时间演化部分之和表示。前一部分是以平行热扩散的耗散形式给出的，涉及无碰撞的减振过程。后者是由长时间平均的陀螺中心分布导出的，在描述低频或定常纬向流时起主要作用，其平行热流用平行流以及非线性源项和初始条件项来表示。分析和数值计算表明，当应用于离子或电子温度梯度湍流驱动的纬向流时，包含新的闭合关系的动力学-流体方程能够再现与回转动力学方程相同的对初始条件和湍流源的长时间纬向流响应。
A novel kinetic-fluid model is presented, which describes collisionless time evolution of zonal flows in tokamaks. In the new zonal-flow closure relations, the parallel heat fluxes are written by the sum of short- and long-time-evolution parts. The former part is given in the dissipative form of the parallel heat diffusion and relates to collisionless damping processes. The latter is derived from the long-time-averaged gyrocenter distribution and plays a major role in describing low-frequency or stationary zonal flows, for which the parallel heat fluxes are expressed in terms of the parallel flow as well as the nonlinear-source and initial-condition terms. It is shown analytically and numerically that, when applied to the zonal flow driven by either ion or electron temperature gradient turbulence, the kinetic-fluid equations including the new closure relations can reproduce the same long-time zonal-flow responses to the initial condition and to the turbulence source as those obtained from the gyrokinetic ...