Modeling the Magnetospheres of Jupiter and Saturn: Influences of the Internal Sources and of the Solar wind.

木星和土星的磁层不同于地球的磁层，其特点是内部有很强的等离子体源（木星的木卫一和土星的土卫二）和快速的自转周期。因此，两个磁层的输运过程与在地球上观察到的非常不同。尽管人们对太阳风和内部源对木星和土星磁层的综合影响很感兴趣，但人们对它们的了解仍然很少。为了研究这些影响，我们将应用并改进一个三维磁流体动力学模型，该模型是我们开发的，用于描述太阳风与木星和土星磁层之间的相互作用。有了这个模型，我们将研究不同的磁层电流系统及其对极光的影响。我们还将研究由于木星倾斜的偶极子场和土星近乎轴对称的磁场而导致的两种磁层之间有趣的差异。我们的模型特别适合这项任务，因为它是目前唯一一个通过包含电离层中性和离子之间的碰撞来处理电离层-磁层耦合的模型。这些碰撞对于获得对变化的内部源和外部变化的太阳风条件的适当响应至关重要。在第二阶段，我们的模型也将被用于研究天王星和海王星的磁层。我们的宏伟目标是通过比较所有四颗外行星的行星学来提高对磁层物理学的普遍理解。

The magnetospheres of Jupiter and Saturn, unlike the magnetosphere of the Earth, are characterized by strong internal plasma sources (Io for Jupiter and Enceladus for Saturn) and a fast rotation period. As a result, transport processes in both magnetospheres are very different from what is observed at Earth. Although of central interest, the combined effects of the solar wind and the internal sources on the magnetospheres of Jupiter and Saturn are still poorly understood. To study these influences, we will apply and improve a three-dimensional magnetohydrodynamic model, which we developed to describe the interactions between the solar wind and the magnetospheres of Jupiter and Saturn. With this model, we will study, among other things, the different magnetospheric current systems and their effects on the aurorae. We will also investigate the interesting differences between both magnetospheres due to the tilted dipole field of Jupiter and the nearly axisymmetric field of Saturn. Our model is particularly well suited for this task as it is currently the only one to treat the ionosphere-magnetosphere coupling through inclusion of collisions between neutrals and ions of the ionosphere. These collisions are crucial to obtain the proper response to changing internal sources and externally varying solar wind conditions. In a second phase, our model will also be adapted to study the magnetospheres of Uranus and Neptune. Our grand aim is to improve the general understanding of magnetospheric physics through comparative planetology of all four outer planets.