Plasma induced atmospheric escape at Mars - A synthesis of Mars Express observations and theory

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The general scientific objective of the proposal is the study of the interaction of the Martian atmosphere with the interplanetary medium. The investigations to be performed will address the fundamental question, how strongly does the solar wind and electromagnetic fields affect the planetary atmosphere? It directly relates to the basic problem of Martian dehydration and the question of whether or not life existed on Mars in the past. If the water was lost due to the direct exposure of the atmosphere by the solar wind, what are the mechanisms of scavenging planetary matter? The answer to this fundamental question requires not only a search of water traces on the planetary surface (the important task of Mars Surveyor missions) but also the study of mechanisms for water outflow. On the other hand, the solar wind not only carries away atmospheric constituents, but can also deposit its matter into the atmosphere. Thus, the study of the solar wind/Mars interaction becomes a fundamental interdisciplinary problem. The global objective of the proposed investigation is to provide a coherent picture how energy is transferred from the solar wind to surrounding regions of the planet and to clarify its environmental effects on the planetary atmosphere. We plan to study this problem by an analysis of the measurements that will be performed on Mars Express by the ASPERA-3 experiment. Access to the data from the Nozomi spacecraft will enhance further the potential of the research. The final product of the research will be a physical model of the escape of the planetary atmosphere, which synthesizes theory, observations and simulations.