We investigate spatial correlation functions (SCFs) at kinetic range in the terrestrial magnetosheath because of wide angular distributions of the magnetic field fluctuations and the high Signal‐to‐Noise‐Ratio. We employ four‐point measurements of magnetic fluctuations from the Cluster and MMS concerning a spatiotemporally varying background magnetic field to constitute the two‐dimensional (2‐D) SCFs between ion and electron scales. It is found that two populations exist in the 2‐D SCFs, with the minority elongated along the perpendicular coordinate (S_⊥) and the majority of population elongated along the coordinate parallel to average magnetic field (S_||). This kind of phenomenon indicates that the distribution of magnetosheath turbulence in the wavenumber space is dominantly transverse to the background magnetic field, simultaneously partly along the field (i.e., k_⊥ >> k_||). In addition, we find that magnetosheath turbulence is the dominance of shear Alfvénic‐like fluctuations, and is quasi‐monofractal intermittent turbulence at kinetic range for both the Cluster case and the MMS case, indicating that strong spatially anisotropic fluctuations may be universal in the magnetosheath. Our observations pose new challenges to the theoretical modeling of turbulence and dissipation at kinetic range in the collisionless magnetized plasma.

中文翻译：

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磁石湍流动力学范围内各向异性空间相关函数的多航天器测量

由于磁场波动的宽角度分布和高信噪比，我们研究了地磁石场动力学范围内的空间相关函数（SCF）。我们使用来自簇和MMS的关于时空变化的背景磁场的四点磁起伏测量来构成离子和电子尺度之间的二维（2-D）SCF。据发现，在2-d SCFS存在两个群体，沿垂直细长少数坐标（小号_⊥）与多数人口沿着坐标平行于平均磁场（细长的小号_||）。这种现象表明，磁鞘湍流在波数空间中的分布是显性横向于背景磁场，同时部分地沿字段（即，ķ _⊥ >> ķ _||）。此外，我们发现磁石场湍流是剪切型Alfvénic波动的主导，并且在Cluster案例和MMS案例的动力学范围内都是准单分形间歇湍流，这表明强的空间各向异性波动可能在磁石场中普遍存在。 。我们的观察结果对无碰撞磁化等离子体中动力学范围内的湍流和耗散的理论模型提出了新的挑战。