Earth's magnetosphere. Artwork of the magnetic field around the Earth (pink,blue and red),showing its interaction with particles from the solar wind (yellow). The Earth's magnetic field is caused by the dynamo process in its core,with fluid flows exciting electric currents. The solar wind is a stream of charged particles,such as protons,flowing from the Sun. The Earth's outer magnetic field,or magnetosphere,is distorted by this wind,forming a bowed shock front on the sunward side and a tail millions of kilometres long on the far side. Some of the particles become trapped in two concentric,doughnut-shaped rings (red) called Van Allen belts |