• Tielong Zhang, Principal Investigator (VEX-MAG), Co-I (ASPERA-4)
• Wolfgang Baumjohann, Co-I (VEX-MAG, ASPERA-4)
• Helfried Biernat, Co-I (VEX-MAG)
• Magda Delva, Co-I (VEX-MAG)
• Herbert Lichtenegger, Co-I (VEX-MAG)
• Rumi Nakamura, Co-I (VEX-MAG)
• Konrad Schwingenschuh, Co-I (VEX-MAG)
• Ute Möstl, Data Analysis, Theory
  
• Hans Ulrich Eichelberger, Data Processing
• Helmut Lammer, Theory
• Martin Volwerk, Data Analysis
• Hannes Gröller, Theory, Modelling

 

 

Venus, like other planets in the solar system, is under the influence of a continuous flow of charged particles from the Sun, the solar wind. However, the lack of an intrinsic magnetic field makes Venus a unique object to study the interaction between solar wind and the planetary body. The planetary body has a dense atmosphere, but no magnetic field, thus the solar wind interacts directly with the upper atmosphere. The absence of a planetary magnetic field leads to important differences between Venus' and Earth's atmospheric escape and energy deposition processes. The upper atmosphere of Venus is not protected by a magnetic field from direct interaction with the solar wind. The figure illustrates associated electrodynamics processes and plasma domains of the Venus upper ionosphere.

The earlier missions, Venera and Pioneer orbiters, found that the current induced by the solar wind electric field forms a magnetic barrier that deflects most of the solar wind flow around the planet and leads to the formation of the bow shock. The ionosphere is terminated on the dayside, developing rapid anti-sunward convection and tail rays. However, the short lifetime of the Venera orbiters, and insufficient temporal resolution of the Pioneer plasma instrument did not allow a study of the mass exchange between the solar wind and the upper atmosphere of Venus and energy deposition to the upper atmosphere in sufficient detail. Venus Express marks a further step forward and perform a detailed study of the structure, chemistry and dynamics of the planet's atmosphere.