Effect of drifts on the diffusion of runaway electrons in tokamak stochastic magnetic fields
Effect of drifts on the diffusion of runaway electrons in tokamak stochastic magnetic fields
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DOI：
10.1063/1.860431
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
J. Myra;P. Catto
中科院分区：
文献类型：
--
作者：
J. Myra;P. Catto
研究了托卡马克随机磁场中失控电子的准线性扩散。先前的模型概括了扰动磁场的空间位置和相干性、电子的径向和极向漂移运动的处理，以及电子漂移运动与所施加的扰动场的跳动所产生的边带的作用。研究发现，漂移效应会降低准线性扩散的水平，其降低量取决于磁湍流的极向分布。在最近的 TEXT 托卡马克实验中，结果被用来估计边缘的内部磁波动水平 [Phys. Fluids B 3, 2038 (1991)]，其中漂移修改效果显示很小。据推断，固有磁湍流控制失控扩散，但不控制背景电子的热扩散率。
The quasilinear diffusion of runaway electrons in tokamak stochastic magnetic fields is examined. Previous models are generalized with respect to the spatial location and coherency of the perturbing magnetic fields, treatment of the radial as well as poloidal drift motion of the electrons, and the role of sidebands that arise from the beating of the electron drift motion with the applied perturbing fields. It is found that drift effects act to reduce the level of quasilinear diffusion by an amount that depends on the poloidal distribution of the magnetic turbulence. The results are employed to estimate the internal magnetic fluctuation levels at the edge during recent experiments on the TEXT tokamak [Phys. Fluids B 3, 2038 (1991)], where the drift modification effects are shown to be small. It is inferred that intrinsic magnetic turbulence controls runaway diffusion, but not the thermal diffusivity of the background electrons.