Quasilinear theory of anisotropy-beta relation for combined mirror and proton cyclotron instabilities
Quasilinear theory of anisotropy-beta relation for combined mirror and proton cyclotron instabilities
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DOI：
10.1029/2012ja017697
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发表时间：
2012-08
影响因子：
--
通讯作者：
P. Yoon;J. Seough
中科院分区：
文献类型：
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作者：
P. Yoon;J. Seough
[1]太阳风和地球的磁鞘通常具有质子温度各向异性的特征，这是绝热流体理论所不能讨论的。当等离子体经受压缩时，可能导致过度的垂直温度各向异性。质子温度各向异性（T_（max）/T_（max）> 1）导致了质子回旋不稳定性和镜不稳定性。这些不稳定性的边缘稳定性条件可以表示为T/T与平行β、β之间的逆相关。在文献中，这些相关性是建立在线性理论、混合模拟或观测拟合的基础上的。本文利用准线性理论研究了质子回旋不稳定性和镜不稳定性。在这样的方法中，逆相关自然地作为自洽演化的时间渐近状态出现。由此建立的反关联表明，在低β介子区，质子回旋不稳定性占主导地位，而在高β介子区，镜像不稳定性决定了反关联。
[1] The solar wind and the Earth's magnetosheath are often characterized by proton temperature anisotropies that cannot be discussed by adiabatic fluid theory. An excessive perpendicular temperature anisotropy may result when the plasma undergoes compression. The proton temperature anisotropy, T⊥/T∥ > 1, leads to the proton cyclotron and mirror instabilities. Marginal stability conditions for these instabilities may be expressed as inverse correlations between T⊥/T∥ and parallel beta, β∥. In the literature, these correlations are constructed on the basis of linear theory, hybrid simulations, or observational fitting. The present paper makes use of quasilinear theory for the proton cyclotron and mirror instabilities. In such an approach the inverse correlation naturally emerges as the time-asymptotic states of self-consistent evolution. The inverse correlation thus constructed shows the predominance of proton cyclotron instability for lowβ∥ regime, while for high β∥ values, the mirror instability dictates the inverse correlation.