Venus and Mars in the solar wind. A Comparative study over four solar cycles.

太阳风中的金星和火星。

• 批准号: 445402550
• 负责人: Privatdozent Dr. Martin Pätzold
• 金额: --
• 依托单位: Space Research Institute
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/445402550?language=en
• 关键词: Venus; Mars; solar; wind.; Comparative

Planets with an intrinsic magnetic field form so-called magnetospheres (a space around the planet dominated by the planetary magnetic field) which protect their atmospheres/ionospheres from the direct interaction and contact with the magnetized plasma flow of the solar wind. There are planets, like Mars and Venus, which do not posses an intrinsic magnetic field and their atmospheres/ionospheres may have direct contact with the solar wind. The magnetized solar wind, however, creates currents in the ionosphere which induce a magnetic field and an induced magnetosphere is formed much closer to the planet, however, than an intrinsic magnetosphere. Despite a wealth of in-situ and remote sensing data collected by many spacecraft over the past four solar cycles, the physics of induced magnetospheres is still insufficiently explored. This project shall focus on the cases of Venus and Mars in order to get a coherent picture of the formation and characteristics of induced magnetosphere. Observations suggest that the structure of their induced magnetospheres is drastically changed by variations of both the solar EUV radiation and the solar wind. A reevaluation of the observational data obtained during the previous missions to Mars and Venus (Pioneer Venus Orbiter (PVO), Venus Express (VEX), Mars Global Surveyor (MGS)) and an analysis of the data from still operational spacecraft (Mars Express (MEX), Mars Atmosphere and Volatile EvolutioN (MAVEN)) shall be performed. The project shall be jointly performed by a collaboration of the two research groups located at the Rheinisches Institut für Umweltforschung (RIU) in Köln, Germany, and the Institute of Space Research (IKI) in Moscow, Russia. The team at RIU shall focus on the study of Venus and Mars ionospheres by a multi-instrument analysis and correlation of observations performed by the PVO, VEX, MGS, MEX and MAVEN spacecraft. This study shall analyze the unmagnetized and magnetized ionospheric states affected by the external drivers (solar EUV flux and solar wind) onto the ionospheres. The magnitude of these external drivers varies with both heliocentric distance and the solar activity and the ionosphere becomes weaker or stronger which may significantly change the physics of the solar wind/ionosphere interaction. The RIU team in this project shall target the analysis of observational to study the main effects of the solar wind/ionosphere interaction, while the IKI team shall examine the theoretical aspects of the induced magnetospheres including the mechanisms of the magnetic field pile-up and the penetration of the interplanetary magnetic fields into the ionosphere at the dayside, problems of the stability and disruption of the magnetic tail. The results shall have relevance for other planets without magnetic fields like Pluto, comets, large moons with atmospheres and in principle also for exoplanets.

具有内在磁场的行星形成所谓的磁层(行星磁场主导的行星周围空间)，保护它们的大气层/电离层不受太阳风的磁化等离子体流的直接作用和接触。有些行星，如火星和金星，没有内在磁场，它们的大气层/电离层可能与太阳风有直接接触。然而，磁化的太阳风在电离层中产生电流，从而感应出磁场，而感应磁层比本征磁层更靠近行星形成。尽管许多航天器在过去的四个太阳周期中收集了大量的现场和遥感数据，但对感应磁层的物理探索仍然不够。该项目将侧重于金星和火星的情况，以便对感应磁层的形成和特征有一个连贯的了解。观测表明，太阳极紫外辐射和太阳风的变化都极大地改变了它们感应磁层的结构。应重新评估在以前的火星和金星飞行任务期间获得的观测数据(先锋金星轨道飞行器(PVO)、金星快车(VEX)、火星全球探测器(MGS))，并对仍在运行的航天器(火星快车(MEX)、火星大气和挥发物演化(MAVEN))的数据进行分析。该项目将由设在德国科恩的莱茵研究所和俄罗斯莫斯科的空间研究所的两个研究小组合作共同实施。RIU的小组将通过对PVO、VEX、MGS、MEX和MAVEN航天器进行的观测进行多仪器分析和相互关联，重点研究金星和火星电离层。这项研究将分析外部驱动因素(太阳极紫外光通量和太阳风)对电离层的非磁化和磁化状态的影响。这些外部驱动力的大小随日心距离和太阳活动而变化，电离层变弱或变强，这可能显着改变太阳风/电离层相互作用的物理学。在这个项目中，国际电离层研究所小组的目标是分析观测数据，以研究太阳风/电离层相互作用的主要影响，而国际电离层研究所小组将研究感应磁层的理论方面，包括磁场堆积的机制和行星际磁场在白天进入电离层的机制、磁尾的稳定性和干扰问题。这一结果将适用于其他没有磁场的行星，如冥王星、彗星、有大气层的大卫星，原则上也适用于系外行星。