Enceladus' plume is the dominant source of neutrals and plasma in Saturn's magnetosphere. The plasma results from the ionization of icy particles and water vapor, which are vented into Saturn's inner magnetosphere through fissures in Enceladus' southern polar region. These fissures are subjected to tidal stresses that can vary as Enceladus moves in a slightly eccentric orbit around Saturn. Plume activity and brightness have also been shown to vary with the moon's orbital position, reaching a maximum when Enceladus is farthest away from Saturn in its orbit (the Enceladus orbital apoapsis). In this paper we will show that temporal variations in the thermal electron density distribution correlate with the position of Enceladus in its orbit around Saturn, with the strongest density enhancements in the vicinity of Enceladus when the moon is in the post‐apoapsis sector of its orbit.

中文翻译：

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土卫二轨道后顶点区域电子密度增强的证据

土卫二磁层中土卫二的主要来源是土卫二的羽状流。等离子体是由冰冷颗粒和水蒸气的电离产生的，它们通过土卫二的南极地区的裂缝排放到土星的内部磁层。这些裂隙承受的潮汐应力会随着土卫二在土星周围稍稍偏心的轨道中移动而变化。羽流的活动性和亮度也已显示出随着月球轨道位置的变化而变化，当土卫二在其轨道上距土星最远时（土卫二轨道脱垂）达到最大值。在本文中，我们将证明热电子密度分布的时间变化与土卫二在土星周围轨道上的位置有关，