Towards realistic models for the interior dynamics of Jupiter and Saturn

木星和土星内部动力学的现实模型

• 批准号: 169822373
• 负责人: Dr. Johannes Wicht
• 金额: --
• 依托单位: Max-Planck-Institut für Sonnensystemforschung (MPS)
• 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 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/169822373?language=en
• 关键词: Towards; realistic; models; interior; dynamics

The majority of numerical dynamo codes where developed with the geodynamo in mind. They neglect the compressibility of the dynamo medium and also assume that the dynamo region dynamically decouples from an overlying electrically insulating body – the rocky mantle in the case of Earth. Both assumptions are justified in the geodynamo context but not for the interior of the gas giants Jupiter and Saturn. Here, the density increases significantly with depth. Also, the dynamo region of these planets is not clearly decoupled from the overlying gas envelope since the increase in electrical conductivity with depth is gradual rather than abrupt. Another interesting feature, which has little been explore so far, is the helium precipitation thought to happen at least in Saturn’s outer layers. It may actually be responsible for the planets peculiar magnetic field. We plan to develop new numerical dynamo models that explore the effects of compressibility, of helium-rain, and of the coupling between the molecular gas envelope and the deeper dynamo region. The latter is one of the key questions for the Juno missions to Jupiter scheduled to be launched in 2011. Our simulations will not only support this mission but also provide realistic models for Saturn’s dynamo in time for the second extended Cassini mission.

大多数数值发电机代码都是在考虑地球发电机的情况下开发的。他们忽略了发电机介质的可压缩性，并且还假设发电机区域与上覆的电绝缘体（在地球的情况下是岩石地幔）动态地解耦。这两种假设在地球动力学的背景下都是合理的，但在气态巨行星木星和土星的内部就不成立了。在这里，密度随着深度的增加而显著增加。此外，由于电导率随深度的增加是渐进的，而不是突然的，这些行星的发电机区域并没有明显地与上覆的气体包层分离。另一个有趣的特征，迄今为止很少被探索，是氦沉淀被认为至少发生在土星的外层。它实际上可能是造成这颗行星特殊磁场的原因。我们计划开发新的数值发电机模型，以探索可压缩性，氦雨以及分子气体包络层与更深的发电机区域之间的耦合的影响。后者是计划于2011年发射的朱诺号木星任务的关键问题之一。我们的模拟不仅将支持这次任务，而且还将为卡西尼号的第二次扩展任务及时提供土星发电机的真实模型。