Magnetosphere. Artwork showing the interaction between the Earth's magnetosphere (blue) and the solar wind (yellow arrows). The solar wind is a stream of charged particles like protons flowing from the Sun. The Earth's outer magnetic field, or magnetosphere, protects the planet from the solar wind but is itself distorted in the process, form- ing a bowed shock front on the sunward side (left) and a tail millions of kilometres long on the far side. Some of the particles become trapped in two concentric, doughnut-shaped rings (orange, shown in cross-section) called Van Allen belts. Earth's magnetic field is produced by molten iron in the central core that swirls as the planet rotates.