The interaction of the shocked solar wind and the planetary ions at Mars

In this study we investigate that region of the dayside magnetosphere of Mars where we may expect that the shocked solar wind comes into direct contact with the planetary ions, and where energy and momentum transfer from the solar wind to planetary plasma may take place. It is our intention to analyse whether the dominant microphysical processes are similar to those observed in the equivalent regions of the magnetosphere of Venus, that is in the dayside mantle of Venus. In this study we present results obtained along the first elliptic orbit of the Phobos 2 spacecraft. Our first conclusion is that around Mars it is the magnetic barrier region that corresponds to the dayside mantle of Venus. In this region at Mars wave excitations are observed, dominantly in the 5 to 50 Hz region; accelerated heavy ions and electrons were also detected. The major conclusion of this study is that despite several observed differences in the way that Venus and Mars interact with the solar wind, the dominant plasma features in the magnetic barrier region of Mars and the dayside mantle of Venus are very similar, indicating that probably the underlying physics is also similar.