Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy.
Space Research Corporation, Annapolis, MD, USA.
Science. 2018 Aug 24;361(6404):774-777. doi: 10.1126/science.aat1450. Epub 2018 Jul 5.
Jupiter's aurorae are produced in its upper atmosphere when incoming high-energy electrons precipitate along the planet's magnetic field lines. A northern and a southern main auroral oval are visible, surrounded by small emission features associated with the Galilean moons. We present infrared observations, obtained with the Juno spacecraft, showing that in the case of Io, this emission exhibits a swirling pattern that is similar in appearance to a von Kármán vortex street. Well downstream of the main auroral spots, the extended tail is split in two. Both of Ganymede's footprints also appear as a pair of emission features, which may provide a remote measure of Ganymede's magnetosphere. These features suggest that the magnetohydrodynamic interaction between Jupiter and its moon is more complex than previously anticipated.
木星的极光产生于其高层大气中，当高能电子沿着行星的磁场线沉降时。可以看到一个北极和一个南极主极光卵形区，周围是与伽利略卫星相关的小发射特征。我们展示了用朱诺号飞船获得的红外观测结果，表明在木卫一的情况下，这种发射呈现出一种类似于卡门涡街的漩涡模式。在主极光点的下游很远的地方，延伸的尾部一分为二。木卫三的两个足迹也呈现出一对发射特征，这可能为木卫三的磁层提供了一种远程测量手段。这些特征表明，木星与其卫星之间的磁流体动力学相互作用比之前预期的更为复杂。
