DFG-RSF: Erosion of the Martian atmosphere by solar wind scavenging - theory and coordinated Mars Express and MAVEN observations

DFG-RSF提案：该建议通过分析火星空间等离子体环境的多航天器（MEX和MAVEN）和多仪器（MaRS、Marsis、ASPERA、LPW、SWIA、MAG、STATIC）数据，解决了太阳风迫使离子从火星大气层逃逸的基本问题。虽然通过MEX在我们对火星空间等离子体环境的了解方面取得了重大进展，但MAVEN航天器的发射首次提供了通过两个航天器同时监测太阳风环境来研究这些过程的独特机会。太阳风是太阳风-电离层-大气耦合的主要驱动力。火星的磁层主要是由太阳风引起的，因此变化很大。虽然多个航天器测量现在是研究日地关系的常用工具，但它将首次将空间变化与时间变化分开，从而为火星研究开辟一个新时代。该项目将（一）对同时观测不同逃逸通道中的离子通量进行一系列综合案例研究，（二）研究逃逸通量对不同控制因素的依赖性：太阳风动压变化，行星际磁场，强太阳事件，地壳磁场，㈢提供一幅太阳风携带的动量如何转移到电离层的连贯画面，㈣将逃逸通量量化为太阳风和行星际磁场输入参数的函数。要研究的物理问题还包括负责在不同的水库逃逸过程的机制。该项目将由科隆Rheinisches Institut fur Umweltforschung RIU和莫斯科伊基空间研究所的两个研究小组合作实施。RIU的研究小组将侧重于利用Marsis在火星快车上进行的无线电掩星和雷达探测观测研究火星电离层的动态，并侧重于两个航天器的现场等离子体测量。伊基小组将研究太阳风和火星电离层之间相互作用的理论方面。只有这样的数据分析和理论建模相结合，才能为我们提供火星周围等离子体环境中物理过程的连贯画面。由这些团队组成的一个新的研究单位计划实现他们积累的潜力，在一个新的更高的水平上研究火星附近的过程。 实验和理论专业知识、数据分析经验和对火星快车实验的密切参与以及与MAVEN科学小组的密切合作，使该小组在研究火星附近空间环境方面处于突出地位，并为实现该提案的目标提供了一个强有力的框架。

DFG-RSF Proposal: This proposal addresses the fundamental question of the ion escape from the atmosphere of Mars forced by the solar wind by analyzing multiple-spacecraft (MEX and MAVEN) and multi-instrument (MaRS, Marsis, ASPERA, LPW, SWIA, MAG, STATIC) data of the Martian space plasma environment. Although a significant progress in our understanding of the Martian space plasma environment was obtained with MEX, the launch of the MAVEN spacecraft provides, for the first time, the unique opportunity to study these processes by the simultaneous monitoring of the solar wind environment by two spacecraft. The solar wind is the main driver for the solar wind-ionosphere-atmosphere coupling. The magnetosphere of Mars is mainly induced by the solar wind and therefore highly variable. Although multiple spacecraft measurements are now a common tool for the study of the Sun-Earth connections, it will open a new era for the investigation of Mars by allowing for the first time to disentangle spatial from temporal variations. This project will (i) conduct a series of comprehensive case studies of simultaneous observations of ion fluxes in different escape channels, (ii) study the dependence of escape fluxes on different controlling factors: variations of solar wind dynamic pressure, interplanetary magnetic field, strong solar events, the crustal magnetic field, (iii) provide a coherent picture how the momentum carried by the solar wind is transferred to the ionosphere, (iv) quantify escape fluxes as a function of the input parameters of the solar wind and the interplanetary magnetic field. The physical problems to be investigated include also the mechanisms responsible for the escape processes in different reservoirs. The project will be performed by the collaborative efforts of the two research groups at Rheinisches Institut für Umweltforschung RIU in Köln, and the Institute of Space Research IKI in Moscow. The team at RIU will focus on the study of the dynamics of the Martian ionosphere using radio-occultation and radar sounding observations performed by Marsis on Mars Express and also on in-situ plasma measurements from both spacecraft. The IKI team will examine theoretical aspects of the interaction between the solar wind and the Mars ionosphere. Only such a combination of data analysis and theoretical modeling can give us a coherent picture of the physical processes in the plasma environment around Mars. A new research unit consisting of these teams plans to realize their accumulated potential to study the processes near Mars on a new higher level. The combination of experimental and theoretical expertise, experience in data analysis and intimate involvement to the experiments on Mars Express and close collaboration with the MAVEN science team put this team in an outstanding position for the study of the space environment near Mars and provides a strong framework for fulfilling the objectives of the proposal.