Toroidal and poloidal magnetic fields at Venus. Venus Express observations

摘要: Abstract Magnetic field and plasma measurements carried out onboard Venus Express during solar minimum conditions suggest the existence of two kinds magnetic configuration in Venusian ionosphere. We interpret these as manifestation different types generation mechanisms for induced magnetosphere. A topology (toroidal poloidal) arises if currents are driven either by wind motional electric or Faraday field—a conducting ionosphere sees a time-varying field. At dayside, both driving agents produce similar draping pattern However, signatures inherent to induction appear at lower altitudes terminator region. The low EUV flux when becomes magnetized seem be favorable distinguish between fields. present cases topology. effects become well noticeable especially interesting since they provide us with an example interaction tiny dipole immersed into Another case poloidal fields evidently displayed is observed IMF vector almost aligned velocity. In general case, probably complement each other.