The wakes and magnetotails of Mars and Venus Original Research Article

The solar wind interaction with the weakly magnetized Mars and Venus differs from the solar wind interaction with the Earth and other strongly magnetized planets in our solar system. A significant difference between magnetized and unmagnetized planets is the standoff distance to the solar wind, the solar wind impacting directly on the topside atmosphere of non-magnetized planets, whilst a strongly magnetized planet fends off the solar wind well above the atmosphere. In fact, neglecting the difference in gravitational pull, there are many similarities between Mars, Venus and comets in terms of their interaction with the solar wind. However, for the nightside tail region the difference between magnetized and non-magnetized celestial objects are less marked. Non-magnetized celestial objects with an atmosphere have, like magnetized objects a magnetotail induced by their interaction with the solar wind. We review the magnetotails of Mars and Venus and compare with observational/visible characteristics of comets. Besides their overall morphology and the general atmospheric outflow/erosion, we also consider the filamentation of ionospheric plasma ejected into the magnetotail from non-magnetized as well as magnetized bodies in the inner part of the solar system.