Field-Aligned Current Systems at Mercury

水星是离太阳最近的轨道行星，因此被嵌入到强烈且高度变化的太阳风中。太阳风与相对较弱的内部磁场的相互作用产生了一个磁层，它的形状与地球的磁层相似，但尺寸要小得多。因此，对地球有效的磁场和电流系统的多种模型可以在一定的限制下应用于水星。一个限制是明显缺乏测量的区域2场对准电流（R2-FAC）系统。在这个项目中，我们将解决这个问题，是否R2-FAC存在于水星与我们的混合模拟代码A.I.K.E.F. . Hermean磁层的当前模型将使用多种方法进行扩展：1。考虑重离子外逸层（巨大的离子陀螺半径可能携带所需的闭合电流），2。包括多壳层电导率模型（预计内行星电流），3。考虑亚阿尔夫文太阳风（不同的电流系统）。通过这些方法，我们将改进现有的平均磁层模型。该模型将与重新分析的MESSENGER现场磁场数据进行比较。了解潜在的R2-FAC的来源将提高我们对独特的Hermean磁层的知识。此外，改进后的水星模型将大大有助于欧空局-日本宇宙航空研究开发机构BepiColombo使命的科学规划。

Planet Mercury is the closest orbiting planet around the sun and is therefore embedded inan intensive and highly varying solar wind. The interaction of the solar wind withthe relatively weak interior magnetic field yields a magnetosphere that is similar in shape but much smaller in size to the magnetosphere of the Earth. Hence, multiple models for the magnetic field and current systems that are valid for Earth can be applied to Mercury with certain restraints. One restraint is the apparent lack of a measured Region 2 field-aligned current (R2-FAC) system. In this project, we will address this question, whether the R2-FAC exist at Mercury with our hybrid simulation code A.I.K.E.F. . The current model of the Hermean magnetosphere will be expanded using multiple approaches: 1. Consideration of a heavy ion exosphere (huge ion gyro radii might carry needed closure currents), 2. Inclusion of a multiple shell conductivity model (inner planetary currents are expected), 3. Consideration of a sub-alfvénic solar wind (different current systems). With these approaches, we will improve the existing average magnetosphere model. The model will be compared against reanalyzed in-situ MESSENGER magnetic field data. Knowing about the sources of potential R2-FAC will improve our knowledge about the unique Hermean magnetosphere. Furthermore, the improved Mercury model will greatly aid in the scientific planning of the upcoming ESA-JAXA BepiColombo mission.