Nonlinear and Non-ideal Effects on FRC Stability
Nonlinear and Non-ideal Effects on FRC Stability
复制标题
对 FRC 稳定性的非线性和非理想影响
DOI：
10.2172/809930
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Yamada
中科院分区：
文献类型：
--
作者：
E. Belova;R. Davidson;H. Ji;M. Yamada
提出了新的计算结果，推进理解的场反转配置（FRC）的稳定性。我们目前的混合动力和双流体（霍尔-MHD）模拟结果的长形FRCs在强动力学和小gyroradius，MHD类制度。详细研究了n = 1倾斜不稳定性的机制和稳定因素，包括非线性和共振粒子效应，粒子损耗沿着开放场线，和霍尔稳定。结果表明，霍尔效应决定的模式旋转和改变的线性模式结构中的动力学制度，然而，在增长率的减少主要是由于有限的拉莫尔半径的影响。共振粒子效应是重要的大回转半径制度，无论分界线的形状，甚至在情况下，当一个大部分的粒子轨道是随机的。粒子损失沿着开放的场线上的倾斜模式具有不稳定的影响，并有助于在环形方向上的离子自旋。在动力学和小回旋半径的FRC的不稳定模式的非线性演化被证明是相当慢的比在MHD模拟。我们的模拟结果表明，动力学和非线性效应的组合是理解更多实验观察到的FRC稳定性的关键。«少
New computational results are presented which advance the understanding of the stability properties of the Field-Reversed Configuration (FRC). We present results of hybrid and two-fluid (Hall-MHD) simulations of prolate FRCs in strongly kinetic and small-gyroradius, MHD-like regimes. The n = 1 tilt instability mechanism and stabilizing factors are investigated in detail including nonlinear and resonant particle effects, particle losses along the open field lines, and Hall stabilization. It is shown that the Hall effect determines the mode rotation and change in the linear mode structure in the kinetic regime; however, the reduction in the growth rate is mostly due to the finite Larmor radius effects. Resonant particle effects are important in the large gyroradius regime regardless of the separatrix shape, and even in cases when a large fraction of the particle orbits are stochastic. Particle loss along the open field lines has a destabilizing effect on the tilt mode and contributes to the ion spin up in toroidal direction. The nonlinear evolution of unstable modes in both kinetic and small-gyroradius FRCs is shown to be considerably slower than that in MHD simulations. Our simulation results demonstrate that a combination of kinetic and nonlinear effects is a key for understanding themore » experimentally observed FRC stability properties.« less