Venus Express science exploitation

Lead Research Organisation: University of Sheffield
Department Name: Automatic Control and Systems Eng


This research proposal outlines a project to study the interaction between the planet Venus and the solar wind, comparing the results to those observed at the Earth. Unlike the Earth, the planet Venus does not possess magnetic field generated within the planet itself. This means that areas of its interaction with the solar wind will be quite different from that observed at the Earth. To begin with, both planets are obstacles in the supersonic solar wind. As a result, both possess a shock wave upstream of the planetary body. This shock wave has to decelerate and deflect the solar wind around the planetary obstacle. Part of the proposal will investigate the processes occurring within and around the shock to determine how the energy from the solar wind is redistributed among the incoming particles. It is also important to determine the thickness of the shock because this has implications on the processes that can occur within the shock and its evolution. Behind the shock lies the magnetosheath, a region of turbulent plasma created from the solar wind as it passed through the shock. The goal of our research in this region is to understand and characterise this turbulence in terms of the processes occurring as the energy redistribution process that started at the shock continues. The boundary at the downstream edge of the magnetosheath differs depending on whether we are studying Earth of Venus. At the Earth, this boundary is the magnetopause and marks the edge of the cavity created be the Earth's magnetic field. At Venus, however, it is the ionosphere that forms the obstacle in the solar wind flow. The boundary that separates the ionosphere from the solar wind flow is the ionopause. Just as the wind can create waves of the surface of a lake, the high speed solar wind can cerate waves on the surface of the ionopause. We will study the generation and evolution of these waves. Sometimes, these waves are so large that they form vortices. At Venus, these vortices will mix plasma from the magnetosheath and ionosphere, which can result in the loss of plasma from the ionosphere. The occurrence, growth and interaction of these vortices will be studied to determine their morphology and dependence on the solar wind conditions and state of the ionosphere. The results of this research will provide a good understanding of how Venus interacts with the solar wind and how this interaction depends upon the current solar wind conditions. The information gained will be of use to planetary and solar physicists as well as astronomers studying objects such as supernovae and galactic jets.


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Zhang TL (2012) Magnetic reconnection in the near Venusian magnetotail. in Science (New York, N.Y.)

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Zhang T (2012) Giant flux ropes observed in the magnetized ionosphere at Venus in Geophysical Research Letters

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Zhang T (2009) Mirror mode structures in the solar wind at 0.72 AU in Journal of Geophysical Research: Space Physics

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Zhang T (2008) Induced magnetosphere and its outer boundary at Venus in Journal of Geophysical Research: Planets

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Walker S (2011) Unusual nonlinear waves in the Venusian magnetosheath DAYSIDE VENUSIAN VORTICES in Journal of Geophysical Research: Space Physics

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Ofman L (2009) Collisionless relaxation of ion distributions downstream of laminar quasi-perpendicular shocks in Journal of Geophysical Research: Space Physics

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Dimmock A (2011) Spatial scales of the magnetic ramp at the Venusian bow shock in Annales Geophysicae

Description Magnetic reconnection has been discovered in the Venusian magnetotail.
The model for the collisionless relaxation of ion distributions downstream of laminar quasi-perpendicular shocks has been developed in relation to kinematic type of collisionless shocks that were identified for the first time by Venus express near Venus.
Giant vortices that may lead to ion escape from Venus have been identified at the boundary of the Venus induced magnetosphere.
Exploitation Route All results are published in leading journals.
Sectors Other