Investigations of Ganymede´s Magnetic Field Environment with new Hubble Space Telescope Observations and Galileo Spacecraft Measurements

利用新的哈勃太空望远镜观测和伽利略航天器测量对木卫三的磁场环境进行调查

• 批准号: 169823901
• 负责人: Professor Dr. Joachim Saur
• 金额: --
• 依托单位: Arbeitsgruppe Weltraumgeophysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/169823901?language=en
• 关键词: Investigations; Ganymede; Magnetic; Field; Environment

Jupiter s satellite Ganymede is the only known satellite in our solar system which possesses a self-generated internal magnetic field. This internal field generates a mini-magnetosphere within Jupiter s large magnetosphere. As Ganymede is constantly moving relative to Jupiter s magnetized plasma, the resulting forces significantly reshape the magnetic field environment of its mini-magnetosphere. Additionally, time varying magnetic field components of Jupiter s magnetosphere induce secondary magnetic fields in a possible electrolytically conductive subsurface water ocean on Ganymede. We will develop and apply three-dimensional numerical models to describe Ganymede s magnetic field environment in order to better understand and disentangle the relative contributions to the magnetic field in Ganymede s vicinity: The dynamo field generated in the core of Ganymede, the plasma fields generated outside of Ganymede, and the induced fields in the possible ocean and also in the core. Our model results will be compared with measurements obtained by the Galileo spacecraft in order to constrain the individual magnetic field contributions. Another focus of our work will be on the morphology of Ganymede s aurora observed by the Hubble Space Telescope. The morphology of Ganymede s auroral oval is diagnostic of its magnetic field environment. Our results will also be directly relevant for a planned future Ganymede orbiter by the European Space Agency.

木星的卫星木卫三是我们太阳系中唯一已知的拥有自生内部磁场的卫星。这个内部磁场在木星的大磁层内产生了一个微型磁层。由于木卫三不断地相对于木星的磁化等离子体移动，所产生的力量显着重塑其微型磁层的磁场环境。此外，木星磁层的时变磁场分量在木卫三上可能的电解导电地下水海洋中感应出次级磁场。我们将开发和应用三维数值模型来描述Ganymede的磁场环境，以便更好地理解和解开Ganymede附近磁场的相对贡献：Ganymede核心中产生的发电机场，Ganymede外部产生的等离子体场，以及可能的海洋和核心中的感应场。我们的模型结果将与伽利略航天器获得的测量结果进行比较，以约束个人的磁场贡献。我们工作的另一个重点是哈勃太空望远镜观测到的木卫三极光的形态。木卫三极光椭圆的形态是其磁场环境的诊断。我们的研究结果也将直接关系到欧洲航天局计划的未来Ganymede轨道器。