A new simulation method is developed for the feedback instability in a magnetosphere-ionosphere coupling system. It solves a gyrokinetic model of the magnetosphere as an initial value problem and properly treats the magnetosphere-ionosphere boundary condition. Linear simulation results confirm that the developed method gives growth rates and frequencies of the feedback instability almost consistent with the most unstable branch solution of the kinetic Alfvén wave predicted by an analytic dispersion relation. The new method also reveals that the plane wave assumption of the magnetosphere made in the derivation of the analytic dispersion relation is partially violated and causes slight underestimation of the growth rate.

中文翻译：

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基于磁层陀螺动力学模型的反馈不稳定性线性稳定性分析

针对磁层-电离层耦合系统中的反馈不稳定性开发了一种新的模拟方法。它将磁层的陀螺动力学模型作为初值问题求解，并妥善处理了磁层-电离层边界条件。线性模拟结果证实，所开发的方法给出的反馈不稳定性的增长率和频率几乎与解析色散关系预测的动力学阿尔文波的最不稳定分支解一致。新方法还表明，在推导解析色散关系时所做的磁层平面波假设被部分违反，导致对增长率的轻微低估。