 The extent of Earth 's magnetic field in space defines the magnetosphere . Ions and electrons of the solar wind are deflected by the magnetosphere ; solar wind pressure compresses the dayside of the magnetosphere , to about 10 Earth radii , and extends the nightside magnetosphere into a long tail . Because the velocity of the solar wind is greater than the speed at which wave propagate through the solar wind , a supersonic bowshock precedes the dayside magnetosphere within the solar wind . Charged particles are contained within the magnetosphere ; the plasmasphere is defined by low @-@ energy particles that essentially follow magnetic field lines as Earth rotates ; the ring current is defined by medium @-@ energy particles that drift relative to the geomagnetic field , but with paths that are still dominated by the magnetic field , and the Van Allen radiation belt are formed by high @-@ energy particles whose motion is essentially random , but otherwise contained by the magnetosphere . 
