Suppression of runaway electron avalanches by radial diffusion
Suppression of runaway electron avalanches by radial diffusion
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DOI：
10.1063/1.1289892
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发表时间：
2000-09
影响因子：
2.2
通讯作者：
P. Helander;L. Eriksson;F. Andersson
中科院分区：
文献类型：
--
作者：
P. Helander;L. Eriksson;F. Andersson
由近距离库仑碰撞引起的失控电子雪崩的动力学理论被扩展以解释径向扩散。人们发现这可以减缓雪崩的增长。导出了增长率的近似解析公式，并通过为此目的构建的三维蒙特卡罗代码进行了验证。由于可用于在托卡马克中感应电场的极向磁通量是有限的，因此可以通过足够强的径向扩散来完全防止雪崩。所需的磁波动水平对模式结构和破坏速度敏感。对于大型托卡马克的典型参数，估计为 δB/B∼10−3。
The kinetic theory of runaway electron avalanches caused by close Coulomb collisions is extended to account for radial diffusion. This is found to slow down the growth of avalanches. An approximate analytical formula for the growth rate is derived and is verified by a three-dimensional Monte Carlo code constructed for this purpose. As the poloidal magnetic flux that is available to induce an electric field in a tokamak is limited, avalanches can be prevented altogether by sufficiently strong radial diffusion. The requisite magnetic fluctuation level is sensitive to the mode structure and the speed of the disruption. It is estimated to be δB/B∼10−3 for parameters typical of large tokamaks.