Surface charging of Saturn's plasma absorbing moons: theoretical estimations and comparisons with Cassini observations
Surface charging of Saturn's plasma absorbing moons: theoretical estimations and comparisons with Cassini observations
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土星等离子体吸收卫星的表面充电：理论估计以及与卡西尼号观测结果的比较
DOI：
10.1029/2010ja015525
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Greg Jones
中科院分区：
文献类型：
--
作者：
E. Roussos;N. Krupp;H. Krüger;Greg Jones
最近对月球与太阳风相互作用的研究结果表明，月球表面的电荷不仅是月球表面与撞击等离子体的局部相互作用的重要物理过程，而且也是带电尘埃喷射和输送的重要物理过程。然而，不包括地球的月球，这样的研究仅限于极少数太阳系天体。在这里，我们评估了表面电荷对土星上吸收等离子体的卫星的重要性。在这项初步研究中，我们重点研究了不同卫星的拖尾半球及其随磁层当地时间变化的充电模式。除了少数例外，我们的结果显示了所有卫星的负势，其中最极端的预测是土卫五。当前半球部分被阳光照射时，表面电势分布可能相当复杂，有许多不同的过渡区。我们还发现，尘埃的静电加速对于亚微米颗粒来说，至少与地球月球的静电加速同等重要(如果不是更重要的话)，但这可能不足以解释在外行星的大卫星附近探测到更大微米尺寸的颗粒的原因。关于土星的小行星大小的卫星，我们预测静电力可以加速颗粒超过逃逸速度，并填充土星系统和/或有助于尘埃通过这些卫星的表面。在此基础上，我们还提出了用卡西尼仪器直接观察表面带电效应的几种方法。
Recent results from the study of the interaction of Earth's moon with the solar wind have highlighted lunar surface charging as an important physical process not only for the local interaction of the surface and the impinging plasma but also for charged dust ejection and transport. Excluding Earth's moon, however, such studies have been limited to very few solar system bodies. Here we assess the importance of surface charging for the Saturnian plasma-absorbing moons. In this initial study, we focus on the various moons' trailing hemispheres and their variable charging patterns as a function of their magnetospheric local time. With only a few exceptions, our results indicate negative potentials for all moons, with the most extreme values predicted for Rhea. When the leading hemisphere is partially sunlit, the surface potential profile can be quite complex with many different transition regions. We also find that electrostatic acceleration of dust is at least equally as (if not more) important as it is for Earth's moon for the submicron grains, but it is probably not sufficient to explain the detection of the larger micron-sized grains in the vicinity of the large moons of the outer planets. Regarding Saturn's asteroid-sized moons, we predict that electrostatic forces can accelerate grains above the escape velocity and populate the Saturnian system and/or contribute to dust transport across those moons' surfaces. On the basis of these results, we also propose several methods by which Cassini's instruments could be used to directly observe the effects of surface charging.
特提斯岛的等离子体尾流：混合模拟与卡西尼号 MAG 数据
影响因子：
5.2
作者：
S. Simon;J. Saur;F.M. Neubauer;U. Motschmann;M.K. Dougherty
通讯作者：
M.K. Dougherty
三个细小的环/弧代表三个小卫星
影响因子：
3.2
作者：
Hedman M
通讯作者：
Hedman M