When Moons Create Aurora: The Satellite Footprints on Giant Planets
When Moons Create Aurora: The Satellite Footprints on Giant Planets
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当卫星创造极光时：巨行星上的卫星足迹
DOI：
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发表时间：
2013
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通讯作者：
B. Bonfond
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作者：
B. Bonfond
极光现象其他行星地球物理Mon © 2012.美国10.1029/2011 GM卫星足迹是木星（土星）上层大气中的极光发射，靠近连接卫星木卫一，木卫二和木卫三（土卫二）的磁场线。它们是这些卫星和它们所围绕的强磁化、快速旋转的行星之间发生的强电磁相互作用的极光特征。木卫一和木卫二的斑点被证明是由一个延长的尾巴。这也可能是木卫三和土卫二排放的情况，尽管还没有明确观测到。此外，主要的木卫一点伴随着二次斑点归因于在木卫一等离子体环面边界上的木卫一产生的等离子体波的反射或电子加速在一个半球，但沉淀在相反的一个。虽然斑点的水平范围暗示了赤道平面上相互作用区域的大小，但足迹的垂直轮廓提供了沉淀电子能量分布的线索。此外，足迹的位置可以用作磁场模型的约束。最后，足迹的亮度是相互作用机制的一个有价值的诊断，并已被观察到在不同的时间尺度上变化，每一个暂时与不同的过程。
Auroral Phenomen Other Planets Geophysical Mon © 2012. American 10.1029/2011GM Satellite footprints are localized auroral emissions in the upper atmosphere of Jupiter (Saturn) near the magnetic field lines linking to satellites, Io, Europa, and Ganymede (Enceladus). They are the auroral signatures of the strong electromagnetic interactions taking place between these moons and the intensely magnetized, rapidly rotating planets they orbit. The Io and Europa spots have been shown to be followed by an extended tail. This might also be the case for the Ganymede and Enceladus emissions, although not yet unambiguously observed. Moreover, the main Io spot is accompanied by secondary spots attributed either to reflections of the plasma waves generated at Io on the Io plasma torus boundary or to electrons accelerated in one hemisphere but precipitating in the opposite one. While the horizontal extent of the spots gives a hint of the size of the interaction region in the equatorial plane, the vertical profile of the footprints provides clues to the energy distribution of the precipitating electrons. Moreover, the location of the footprints can be used as constraints for magnetic field models. Finally, the brightness of the footprints is a valuable diagnostic of the interaction mechanism and has been observed to vary at different time scales, each one tentatively associated with a different process.