AI 中文总结
该研究通过三维混合模拟表征地球湍流磁层鞘的异常电场，提出解释异常电阻率与输运平衡的框架，测试亚格子模型发现其无法完全恢复相位相干性，揭示异常电场的耦合与非线性作用。
AI 中文摘要
在碰撞等离子体和无碰撞等离子体中，广泛存在的电磁和等离子体涨落会产生异常电场，这些电场对系统的动力学演化至关重要，例如在磁重联、等离子体湍流和发电机理论中的情况。在尺度大于离子惯性长度的等离子体湍流背景下，等离子体满足冻结条件，异常电场由湍流速度场和磁场之间的相关性产生。相反，对于无碰撞等离子体且在动力学尺度下，总电场有额外贡献，这些贡献来自动力学现象，即电荷分离、双极电场和电子惯性，且每个项都有对应的异常形式。本研究对异常电场进行了表征，提出了一个可解释异常电阻率与异常输运之间部分平衡的框架，并利用该框架研究动力学尺度下的异常电场。我们明确了异常电场的不同贡献如何与大尺度电场耦合，且异常项会反作用于磁场结构，可能促成有效的湍流磁扩散或屏蔽。最后，我们测试了两个包含各向异性输运系数的亚格子尺度模型，结果显示尽管这些模型能部分恢复谱信息，但无法完全恢复相位相干性，这表明异常项对解析尺度的贡献存在更复杂的非线性作用。
英文摘要
In both collisional and collisionless plasmas the presence of a broad range of electromagnetic and plasma fluctuations provides anomalous electric fields that can be important for the dynamical evolution of the system as it is the case of magnetic reconnection, plasma turbulence and dynamo theory. In the context of plasma turbulence at scales larger than the ion's inertial length, the plasma satisfies the frozen-in condition, and the anomalous electric fields are produced by correlations between turbulent velocity and magnetic fields. Conversely, for collisionless plasmas and at kinetic scales, the total electric field has additional contributions that arise from kinetic phenomena, namely, charge separation, ambipolar electric fields and electron inertia, and each of these terms presents an anomalous counterpart. In this work we characterize the anomalous electric fields. We present a framework that can explain partial balance between the anomalous resistivity and anomalous transport, and we use it to study anomalous electric fields at kinetic scales. We establish how the different contributions to the anomalous electric field couple to the large-scale electric fields and show that the anomalous terms act back-reacting on magnetic-field organization and they may contribute to effective turbulent magnetic diffusion or shielding. Finally, we test two Sub-Grid-Scale models including anisotropic transport coefficients and show that although these models partially recover the spectral information, the phase coherence is not entirely recovered by these models suggesting a more complex non-linear contribution of the anomalous terms to the resolved scales.
Comments28 Pages, 8 Figures, one table
