Magnetic trap

Magnetic trap

Fig. 3.15 . Charged particles can be trapped by Earth’s magnetic field. They bounce back and forth between polar mirror points in either hemisphere at intervals of seconds to minutes, or they also drift around the planet on time scales of hours. As shown by the Norwegian scientist Carl Størmer (1874-1957) in 1907, with the trajectories shown here, the motion is turned around by the stronger magnetic fields near the Earth’s magnetic poles. Because of their positive and negative charge, the protons and electrons drift in opposite directions.

Copyright 2010, Professor Kenneth R. Lang, Tufts University