Malaspina D M, Goodrich K, Livi R, Halekas J, McManus M, Curry S, Bale S D, Bonnell J W, de Wit T Dudok, Goetz K, Harvey P R, MacDowall R J, Pulupa M, Case A W, Kasper J C, Korreck K E, Larson D, Stevens M L, Whittlesey P
Department of Astrophysical and Planetary Sciences University of Colorado Boulder Boulder CO USA.
Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder CO USA.
Geophys Res Lett. 2020 Oct 28;47(20):e2020GL090115. doi: 10.1029/2020GL090115. Epub 2020 Oct 19.
The solar wind is slowed, deflected, and heated as it encounters Venus's induced magnetosphere. The importance of kinetic plasma processes to these interactions has not been examined in detail, due to a lack of constraining observations. In this study, kinetic-scale electric field structures are identified in the Venusian magnetosheath, including plasma double layers. The double layers may be driven by currents or mixing of inhomogeneous plasmas near the edge of the magnetosheath. Estimated double-layer spatial scales are consistent with those reported at Earth. Estimated potential drops are similar to electron temperature gradients across the bow shock. Many double layers are found in few high cadence data captures, suggesting that their amplitudes are high relative to other magnetosheath plasma waves. These are the first direct observations of plasma double layers beyond near-Earth space, supporting the idea that kinetic plasma processes are active in many space plasma environments.
当太阳风遇到金星的感应磁层时，其速度会减慢、方向会偏转并被加热。由于缺乏具有约束性的观测数据，动力学等离子体过程对这些相互作用的重要性尚未得到详细研究。在这项研究中，在金星磁鞘中识别出了动力学尺度的电场结构，包括等离子体双层。双层可能由磁鞘边缘附近的电流或不均匀等离子体的混合驱动。估计的双层空间尺度与在地球观测到的一致。估计的电位降与越过弓形激波的电子温度梯度相似。在少数高时间分辨率的数据记录中发现了许多双层，这表明它们的振幅相对于其他磁鞘等离子体波较高。这些是近地空间以外首次对等离子体双层进行的直接观测，支持了动力学等离子体过程在许多空间等离子体环境中都很活跃的观点。
