论文标题
重新访问Ulysses电子数据，具有三重速度分布
Revisiting the Ulysses electron data with a triple fit of velocity distributions
论文作者
论文摘要
鉴于它们的独特性，Ulysses数据仍然可以为我们提供有关在太阳风中等离子体种群的特性的宝贵新线索，尤其是关于它们与热力照相坐标的变化。 We revisit the electron data reported by by the SWOOPS instrument on-board of the Ulysses spacecraft between 1990 to early 2008. These observations reveal velocity distributions out of thermal equilibrium, with anisotropies (e.g., parallel drifts or/and different temperatures, parallel and perpendicular to the background magnetic field), and quasi-thermal and suprathermal populations with different properties.我们使用Levenberg-Marquardt算法应用2D非线性最小平方拟合程序，同时拟合速度电子数据（高达几个KEV）与三个不同模型结合了三个不同的群体：较中央的Quasi-thermal核心和超级卤代halo和第二个偏移的群体，以及一个构成的超脑群，或者是一个组合的群体，或者是构成的（或一个均匀的群体）（或者是均匀的群体（均为众多）（均匀的范围）（均为众多的群体（占地）（均为占地面积）（漂移）。最近引入的$κ$ -Cookbook用于描述每个组件，具有以下各向异性分布功能（食谱）：Maxwellian，正规化的Kappa-和广义Kappa-Distriputions。通过最佳拟合定量的温度各向异性被认为是表征电子种群的主要参数的案例研究。与核心相比，两个外炎都表现出较高的温度各向异性，随着电子能量的增加而略有增加。
Given their uniqueness, the Ulysses data can still provide us with valuable new clues about the properties of plasma populations in the solar wind, and, especially, about their variations with heliographic coordinates. We revisit the electron data reported by by the SWOOPS instrument on-board of the Ulysses spacecraft between 1990 to early 2008. These observations reveal velocity distributions out of thermal equilibrium, with anisotropies (e.g., parallel drifts or/and different temperatures, parallel and perpendicular to the background magnetic field), and quasi-thermal and suprathermal populations with different properties. We apply a 2D nonlinear least square fitting procedure, using the Levenberg-Marquardt algorithm, to simultaneously fit the velocity electron data (up to a few keV) with a triple model combining three distinct populations: the more central quasi-thermal core and suprathermal halo, and a second suprathermal population consisting mainly of the electron strahl (or beaming population with a major field-aligned drift). The recently introduced $κ$-cookbook is used to describe each component with the following anisotropic distribution functions (recipes): Maxwellian, regularized kappa-, and generalized kappa-distributions. The temperature anisotropy quantified by the best fits is considered as a case study of the main parameters characterizing electron populations. By comparison to the core, both suprathermal populations exhibit higher temperature anisotropies, which slightly increase with the energy of electrons.
