The Magnetosphere and Ionosphere

Abstract

Abstract The solar wind compresses the geomagnetic field on the day side of the Earth and drags it out on the night side into a long magnetotail. The space occupied by the deformed field is the magnetosphere. Charged particles that penetrate it are trapped by geomagnetic field lines and shuttle between the polar regions. Two doughnut-shaped zones of intense radiation, called the Van Allen belts, girdle the Earth at altitudes between 1,000 km 60,000 km. Solar radiation ionizes atoms in the upper atmosphere to form the ionosphere. Electrical currents in the ionosphere produce magnetic fields that induce electrical currents in the Earth. They vary with the amount of insolation. The Earth’s rotation causes a daily change in the field at Earth’s surface. Long-period changes in the field penetrate the mantle, enabling scientists to measure its electrical conductivity. Extreme solar activity, in particular solar storms, can severely damage satellites and infrastructure on Earth.