This study presents evidence of stably trapped electrons at Jupiter's moon Ganymede. We model energetic electron pitch angle distributions and compare them to observations from the Galileo Energetic Particle Detector to identify signatures of trapped particles during the G28 encounter. We trace electron trajectories to show that they enter Ganymede's mini-magnetospheric environment, become trapped, and drift around the moon for up to 30 min, in some cases stably orbiting the moon multiple times. Conservation of the first adiabatic invariant partially contributes to energy changes throughout the electrons' orbits, with additional acceleration driven by local electric fields, before they return to Jupiter's magnetosphere or impact the surface. These trapped particles manifest as an electron population with an enhanced flux compared to elsewhere within the mini-magnetosphere that are detectable by future spacecraft.

中文翻译：

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木卫三俘获电子辐射带的形成

这项研究提供了木星卫星木卫三上稳定捕获电子的证据。我们对高能电子俯仰角分布进行建模，并将其与伽利略高能粒子探测器的观测结果进行比较，以识别 G28 遭遇期间被捕获粒子的特征。我们追踪电子轨迹，发现它们进入木卫三的迷你磁层环境，被困住，并绕月球漂移长达 30 分钟，在某些情况下稳定地绕月球运行多次。第一个绝热不变量的守恒部分有助于整个电子轨道的能量变化，并在它们返回木星磁层或撞击表面之前由局部电场驱动额外的加速。这些被捕获的粒子表现为电子群，与未来航天器可检测到的微型磁层内的其他地方相比，其通量增强。