发表机构
Aix-Marseille Université, CNRS, CNES, Institut Origines, LAM; Laboratory of Planetary and Atmospheric Physics, STAR Institute, University of Liège; Université de Toulouse, CNRS, CNES, Institut de Recherche en Astrophysique et Planétologie; Institut Supérieur de l’Aéronautique et de l’Espace (ISAE SUPAERO), Université de Toulouse; Weihai Institute for Interdisciplinary Research, Shandong University; Johns Hopkins University Applied Physics Laboratory; Space Science and Engineering Division, Southwest Research Institute（艾克斯-马赛大学，法国国家科学研究中心，法国国家空间研究中心，起源研究所，天体物理学与行星学实验室; 列日大学，STAR研究所，行星与大气物理实验室; 图卢兹大学，法国国家科学研究中心，法国国家空间研究中心，天体物理学与行星学研究所以; 图卢兹大学，航空航天高级学院; 山东大学，威海交叉科学研究院; 约翰斯·霍普金斯大学应用物理实验室; 西南研究院，空间科学与工程部）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用Juno/JADE和JEDI数据，提出4-kappa分布模型，准确拟合木星六个极光子区域的沉降电子能谱，并揭示其能量沉积特性，为极光建模提供新框架。
AI 中文摘要
木星的极光是由磁层电子沉降到其大气中产生的。Juno/JADE和Juno/JEDI共同测量了能量从100 eV到1 MeV的这些电子。然而，它们的极光光谱很难被广泛使用的kappa分布（以下称为经典单kappa分布）所重现。我们旨在统计表征沉降极光电子的能量通量分布，并推导出一种更适合JADE+JEDI数据的新现象学4-kappa分布。我们构建了六个极光子区域（两个半球的极区、主发射区和外发射区）的平均能量通量分布，结合了PJ3至PJ35的JADE和JEDI数据，并使用包含电流片的JRM33模型映射到SIII坐标系。我们使用经典单kappa分布和4-kappa分布通过MCMC进行拟合。平均分布显示出单调的幂律衰减，在大多数子区域中能量截止超过约500 keV，尽管一些单独的光谱在中等能量处偏离这一趋势。平均能量范围约为21至119 keV，能量通量范围约为9.5至28.7 mW/m²。经典单kappa拟合在所有子区域均失败，κ收敛到其先验范围的下限。因此，我们引入了4-kappa分布，它是四个经典单kappa分布的线性组合，并受指数高能截止调制，能够准确拟合所有六个子区域。在相同能量通量和平均能量下，输运模拟表明，4-kappa分布比经典分布将能量沉积在更低的高度，并沿垂直方向以不同方式分布能量，这对紫外颜色比、大气化学和热结构以及电离层电导率有影响。该分布为木星电子沉降和紫外极光发射的现实建模提供了一个分析框架。
英文摘要
Jupiter's auroras are produced by magnetospheric electrons precipitating into its atmosphere. Juno/JADE and Juno/JEDI together measure these electrons from 100 eV to 1 MeV. However, their auroral spectra are poorly reproduced by the widely used kappa distribution, hereafter the classical single-kappa distribution. We aim to statistically characterize the energy flux distributions of precipitating auroral electrons and to derive a new phenomenological 4-kappa distribution better suited to JADE+JEDI data. We build mean energy flux distributions in six auroral sub-regions (polar, main, and outer emissions in both hemispheres), combining JADE and JEDI data from PJ3 to PJ35, mapped to the SIII frame with the JRM33 model including the current sheet. We fit them using MCMC with the classical single-kappa and 4-kappa distributions. The mean distributions show a monotonic power-law decay with an energy cutoff beyond ~500 keV in most sub-regions, although some individual spectra depart from it at intermediate energies. Mean energies range from ~21 to ~119 keV, and energy fluxes from ~9.5 to ~28.7 mW/m$^2$. The classical single-kappa fit fails in all sub-regions, with $κ$ converging to the lower bound of its prior range. We therefore introduce the 4-kappa distribution, a linear combination of four classical single-kappa distributions modulated by an exponential high-energy cutoff, which accurately fits all six sub-regions. At equal energy flux and mean energy, transport simulations show that the 4-kappa distribution deposits energy at lower altitude than the classical one and distributes it differently along the vertical, with implications for the UV color ratio, atmospheric chemistry and thermal structure, and ionospheric conductances. This distribution provides an analytical framework for realistic modeling of electron precipitation and UV auroral emissions at Jupiter.
Comments16 pages, 8 figures, submitted to Astronomy & Astrophysics
