Non-linear mirror instability
Non-linear mirror instability
复制标题
非线性镜不稳定性
DOI：
--
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
S. Cowley
中科院分区：
文献类型：
--
作者：
F. Rincon;F. Rincon;A. Schekochihin;S. Cowley
磁场强度的缓慢动态变化和粒子磁矩的不变性在弱碰撞的磁化天体物理等离子体中产生了普遍存在的压力各向异性。这使得它们不稳定的快速，小规模的镜像和消防水龙带不稳定性，这是能够施加反馈的宏观动力学系统。通过一个新的渐近理论的早期非线性演化的镜像不稳定性在等离子体受到缓慢剪切或压缩，我们表明，不稳定性不饱和准线性稳定，低振幅水平。相反，在小尺度的镜子粒子的捕获导致非线性长期增长的磁扰动，$\delta B/B \propto t^{2/3}$。我们的理论解释了最近的无碰撞模拟结果，提供了一个预测的镜像演化在弱碰撞等离子体和建立一个理论基础的非线性镜动力学与捕获，有效的到$\delta B/B =O（1）$。
Slow dynamical changes in magnetic-field strength and invariance of the particles' magnetic moments generate ubiquitous pressure anisotropies in weakly collisional, magnetized astrophysical plasmas. This renders them unstable to fast, small-scale mirror and firehose instabilities, which are capable of exerting feedback on the macroscale dynamics of the system. By way of a new asymptotic theory of the early nonlinear evolution of the mirror instability in a plasma subject to slow shearing or compression, we show that the instability does not saturate quasilinearly at a steady, low-amplitude level. Instead, the trapping of particles in small-scale mirrors leads to nonlinear secular growth of magnetic perturbations, $\delta B/B \propto t^{2/3}$. Our theory explains recent collisionless simulation results, provides a prediction of the mirror evolution in weakly collisional plasmas and establishes a foundation for a theory of nonlinear mirror dynamics with trapping, valid up to $\delta B/B =O(1)$.
空间等离子体中的镜像不稳定性：孤子和椭圆曲线波
影响因子：
2.2
作者：
Istomin Y
通讯作者：
Istomin Y