L. Bonalumi, E. Alessi, E. Lazzaro, S. Nowak, C. Sozzi, D. Frigione, L. Garzotti, E. Lerche, F. Rimini, D. van Eester
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引用次数: 0
摘要
本研究通过评估一组 JET 干扰的广义卢瑟福方程 (GRE) 的非线性项,解决了新古典撕裂模式的触发问题。线性稳定指数Δ′0,即使是正值,也不足以描述模式的触发,因为稳定非线性效应往往会阻止低于一定宽度的模式增长。首先,分析了曲率的稳定效应和自举的失稳效应的贡献。其次,工作重点是离子极化电流的作用,即由于电子和离子漂移运动的差异而产生的平行于磁场的返回电流。这一贡献被认为在宽度为 W 的磁岛出现时起着重要作用,因为它的比例为 1/W3,当 W 较小时,它是 GRE 中的主要项。评估是在一个脉冲子集上进行的,产生了一些有趣的观察结果,然后将这些观察结果推广到整个数据库中,得到了一致的结果。
Analysis of the role of the ion polarization current on the onset of pre-disruptive magnetic islands in JET
The problem of the trigger of the neoclassical tearing mode is addressed in this work by evaluating the non-linear terms of the generalized Rutherford equation (GRE) for a set of JET disruptions. The linear stability index Δ′0, even for positive values, is not enough to describe the trigger of the mode as the stabilizing non-linear effects tend to prevent the growth of a mode below a certain width. First, an analysis on the contribution of the stabilizing effect of the curvature and the destabilizing effect of the bootstrap is done. Second, the work focuses on the role of the ion polarization current, a return current that flows parallel to the magnetic field due to the difference in the drift motion of the electrons and ions. This contribution is thought to play an important role in the onset of an island of width W, because it scales as 1/W3, making it a dominant term in the GRE when W is small. The assessment is carried out over a subset of pulses, producing interesting observations that were then generalized across the entire database, obtaining consistent results.