Ion Bernstein instability in the terrestrial magnetosphere: Linear dispersion theory
Ion Bernstein instability in the terrestrial magnetosphere: Linear dispersion theory
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DOI：
10.1029/2010ja015965
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发表时间：
2010-12
影响因子：
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通讯作者：
S. Gary;Kaijun Liu;D. Winske;R. Denton
中科院分区：
文献类型：
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作者：
S. Gary;Kaijun Liu;D. Winske;R. Denton
[1]利用均匀磁化无碰撞等离子体中电磁涨落的线性动力学色散理论，研究了质子速度分布fp（v）满足φ fp（v）/φ v φ> 0时离子伯恩斯坦模不稳定性的性质，其中φ表示垂直于背景磁场Bo的方向.这里fp（v）= f1（v）− f2（v），其中f1和f2是麦克斯韦速度分布，密度和温度略有不同;等离子体参数来自磁层观测。那么这种不稳定性的增长率在ωr <$nΩp处有相对最大值，其中n = 1，2，3，.，Ωp是质子回旋频率;波矢k在0 < k <$<$k <$，其中<$和<$表示平行和垂直于Bo的方向;波长在质子回旋半径的量级或更小。最大不稳定性增长率是电子-质子温度比的单调递减函数，但在质子β的中间值处具有最大值（对于此处考虑的参数为1.0.5）。
[1] Linear kinetic dispersion theory for electromagnetic fluctuations in a homogeneous, magnetized, collisionless plasma is used to study the properties of an ion Bernstein mode instability driven by a proton velocity distribution fp(v) such that ∂fp(ν⊥)/∂ν⊥ > 0, where ⊥ denotes directions perpendicular to the background magnetic field Bo. Here fp(v) = f1(ν) − f2(ν), where f1 and f2 are Maxwellian velocity distributions with slightly different densities and temperatures; plasma parameters are taken from magnetospheric observations. Then the growth rate of this instability has relative maxima at ωr ≃ nΩp, where n = 1, 2, 3, … and Ωp is the proton cyclotron frequency; wave vector k at 0 < k∥ ≪ k⊥, where ∥ and ⊥ denote the directions parallel and perpendicular to Bo; and wavelengths of the order of or smaller than the proton gyroradius. The maximum instability growth rate is a monotonically decreasing function of the electron-to-proton temperature ratio but has its largest value at an intermediate value of the proton β (∼0.5 for the parameters considered here).