What type of magnetic field is produced around Venus by the solar wind?

Venus has an induced magnetic field produced by the interaction between the solar wind and its ionosphere. Unlike Earth, Venus does not have a strong intrinsic magnetic field generated by an internal dynamo.

The solar wind carries the Sun’s magnetic field past Venus. As that charged plasma encounters Venus’s upper atmosphere, it ionizes gases and drives electrical currents. Those currents create a surrounding induced magnetosphere, including a bow shock, magnetosheath, magnetopause, and long magnetotail.

This is different from a dipole magnetic field, such as Earth’s main magnetic field, which is generated deep inside the planet by moving electrically conductive material in its outer core. Venus is similar to Earth in size, so its lack of an internal dynamo has long been an important planetary-science question.

The induced field offers limited protection. Solar-wind interactions can help carry hydrogen, oxygen, and other ions away from Venus, contributing to atmospheric erosion. The term “fossil magnetic field” refers to remanent magnetism in rocks, while a toroidal field is a different field geometry.