Kinetic Effects on the Stability Properties of Field-reversed Configurations: II. Nonlinear Evolution
Kinetic Effects on the Stability Properties of Field-reversed Configurations: II. Nonlinear Evolution
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DOI：
10.2172/820209
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发表时间：
2003-11
期刊：
影响因子：
--
通讯作者：
E. Belova;R. Davidson;H. Ji;M. Yamada
中科院分区：
文献类型：
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作者：
E. Belova;R. Davidson;H. Ji;M. Yamada
场反转组态（FRC）的三维混合模拟的结果。本文的重点是研究动态FRC中磁流体动力学不稳定性的非线性演化。考虑了宽范围的“bar s”值，其中“bar s”是FRC动力学参数，其测量配置中的离子回旋半径的数量。研究了环模数n ≥ 1的MHD模的线性和非线性稳定性，包括离子旋转、有限电子压和弱环向场的影响。低“bar s”模拟显示n = 1倾斜模式的非线性饱和。n大于或等于2的旋转模式被观察到增长的倾斜不稳定性的非线性阶段期间，由于离子自旋在环形方向。大的“bar s”模拟表明倾斜模式没有饱和，并且在初始快速线性增长之后，不稳定性有缓慢的非线性演化。总的来说，混合动力模拟证明了非线性效应的重要性，这是负责饱和的不稳定性在低“酒吧s”配置，也为FRC寿命的增加相比，MHD模型在高“酒吧s”配置。
Results of three-dimensional hybrid simulations of the field-reversed configuration (FRC) are presented. Emphasis of this work is on the nonlinear evolution of magnetohydrodynamic (MHD) instabilities in kinetic FRCs. A wide range of ''bar s'' values is considered, where the ''bar s'' is the FRC kinetic parameter, which measures the number of ion gyroradii in the configuration. The linear and nonlinear stability of MHD modes with toroidal mode numbers n greater than or equal to 1 is investigated, including the effects of ion rotation, finite electron pressure, and weak toroidal field. Low-''bar s'' simulations show nonlinear saturation of the n = 1 tilt mode. The n greater than or equal to 2 rotational modes are observed to grow during the nonlinear phase of the tilt instability due to ion spin-up in the toroidal direction. Large-''bar s'' simulations show no saturation of the tilt mode, and there is a slow nonlinear evolution of the instability after the initial fast linear growth. Overall, the hybrid simulations demonstrate the importance of nonlinear effects, which are responsible for the saturation of instabilities in low-''bar s'' configurations, and also for the increase in FRC life-time compared to MHD models in high-''bar s'' configurations.