ON QUIET-TIME SOLAR WIND ELECTRON DISTRIBUTIONS IN DYNAMICAL EQUILIBRIUM WITH LANGMUIR TURBULENCE
ON QUIET-TIME SOLAR WIND ELECTRON DISTRIBUTIONS IN DYNAMICAL EQUILIBRIUM WITH LANGMUIR TURBULENCE
复制标题
朗缪尔湍流动态平衡中安静时太阳风电子分布
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
P. Yoon
中科院分区：
文献类型：
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作者：
S. Zaheer;P. Yoon
最近的一系列论文提出了渐近稳态电子分布函数和朗缪尔湍流强度的自洽理论。该理论是根据 κ 分布发展起来的，该分布具有麦克斯韦低能电子和非麦克斯韦高能幂律尾部分量。本文讨论了一种广义 κ 分布，其特征是 Davydov-Druyvesteyn 类型的核心成分和能量幂律尾部成分。这种概括的物理动机是使模型可以反映低能电子与低频动能阿尔芬尼克湍流以及高频朗缪尔湍流相互作用的影响。结果表明，该解及其伴随的朗缪尔波谱严格满足粒子和波动力学方程中自发发射过程和诱导发射过程之间的平衡要求，并且近似满足非线性自发散射过程和诱导散射过程之间的类似平衡要求。尽管对电子分布函数进行了低速修改，但结果表明，所得到的渐近速度幂律指数α，其中fe∼v−α接近于安静时间太阳风条件下观测到的平均指数，即根据观测，αaverage∼6.69。
A recent series of papers put forth a self-consistent theory of an asymptotically steady-state electron distribution function and Langmuir turbulence intensity. The theory was developed in terms of the κ distribution which features Maxwellian low-energy electrons and a non-Maxwellian energetic power-law tail component. The present paper discusses a generalized κ distribution that features a Davydov–Druyvesteyn type of core component and an energetic power-law tail component. The physical motivation for such a generalization is so that the model may reflect the influence of low-energy electrons interacting with low-frequency kinetic Alfvénic turbulence as well as with high-frequency Langmuir turbulence. It is shown that such a solution and the accompanying Langmuir wave spectrum rigorously satisfy the balance requirement between the spontaneous and induced emission processes in both the particle and wave kinetic equations, and approximately satisfy the similar balance requirement between the spontaneous and induced scattering processes, which are nonlinear. In spite of the low velocity modification of the electron distribution function, it is shown that the resulting asymptotic velocity power-law index α, where fe ∼ v−α is close to the average index observed during the quiet-time solar wind condition, i.e., whereas αaverage ∼ 6.69, according to observation.